20121276640 has 192 divisors, whose sum is σ = 52254720000. Its totient is φ = 7292989440.

The previous prime is 20121276631. The next prime is 20121276641. The reversal of 20121276640 is 4667212102.

It is a Harshad number since it is a multiple of its sum of digits (31).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (20121276641) by changing a digit.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 8386161 + ... + 8388559.

It is an arithmetic number, because the mean of its divisors is an integer number (272160000).

Almost surely, 2^20121276640 is an apocalyptic number.

20121276640 is a gapful number since it is divisible by the number (20) 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 20121276640, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (26127360000).

20121276640 is an abundant number, since it is smaller than the sum of its proper divisors (32133443360).

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

20121276640 is a wasteful number, since it uses less digits than its factorization.

20121276640 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2553 (or 2545 counting only the distinct ones).

The product of its (nonzero) digits is 8064, while the sum is 31.

Adding to 20121276640 its reverse (4667212102), we get a palindrome (24788488742).

The spelling of 20121276640 in words is "twenty billion, one hundred twenty-one million, two hundred seventy-six thousand, six hundred forty".