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121111216128 = 215327217229

121111216128 has 864 divisors, whose sum is σ = 447250816350. Its totient is φ = 31444697088.

The previous prime is 121111216123. The next prime is 121111216147. The reversal of 121111216128 is 821612111121.

Adding to 121111216128 its reverse (821612111121), we get a palindrome (942723327249).

121111216128 is a `hidden beast` number, since 1 + 2 + 11 + 11 + 21 + 612 + 8 = 666.

It can be written as a sum of positive squares in 3 ways, for example, as 120236949504 + 874266624 = 346752^2 + 29568^2 .

It is a nude number because it is divisible by every one of its digits and also a Zuckerman number because it is divisible by the product of its digits.

It is an insolite number, because it is divisible by the sum (119) and by the product (147456) of the squares of its digits.

It is not an unprimeable number, because it can be changed into a prime (121111216123) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 53 ways as a sum of consecutive naturals, for example, 4176248818 + ... + 4176248846.

Almost surely, 2121111216128 is an apocalyptic number.

121111216128 is a gapful number since it is divisible by the number (18) formed by its first and last digit.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 121111216128, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (223625408175).

121111216128 is an abundant number, since it is smaller than the sum of its proper divisors (326139600222).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

121111216128 is an equidigital number, since it uses as much as digits as its factorization.

121111216128 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 113 (or 58 counting only the distinct ones).

The product of its digits is 384, while the sum is 27.

The spelling of 121111216128 in words is "one hundred twenty-one billion, one hundred eleven million, two hundred sixteen thousand, one hundred twenty-eight".