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21111311232 = 27351161703

21111311232 has 192 divisors, whose sum is σ = 68728383360. Its totient is φ = 6397263360.

The previous prime is 21111311227. The next prime is 21111311239. The reversal of 21111311232 is 23211311112.

Adding to 21111311232 its reverse (23211311112), we get a palindrome (44322622344).

It is a tau number, because it is divible by the number of its divisors (192).

It is a Harshad number since it is a multiple of its sum of digits (18).

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 (36) and by the product (5184) of the squares of its digits.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21111311239) by changing a digit.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 311293 + ... + 372995.

It is an arithmetic number, because the mean of its divisors is an integer number (357960330).

Almost surely, 221111311232 is an apocalyptic number.

21111311232 is a gapful number since it is divisible by the number (22) 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 21111311232, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (34364191680).

21111311232 is an abundant number, since it is smaller than the sum of its proper divisors (47617072128).

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

21111311232 is an equidigital number, since it uses as much as digits as its factorization.

21111311232 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 61743 (or 61719 counting only the distinct ones).

The product of its digits is 72, while the sum is 18.

The spelling of 21111311232 in words is "twenty-one billion, one hundred eleven million, three hundred eleven thousand, two hundred thirty-two".