21902156640 has 1152 divisors, whose sum is σ = 98802063360. Its totient is φ = 4317401088.

The previous prime is 21902156621. The next prime is 21902156641. The reversal of 21902156640 is 4665120912.

21902156640 is a `hidden beast` number, since 2 + 1 + 9 + 0 + 2 + 1 + 5 + 6 + 640 = 666.

It is a Harshad number since it is a multiple of its sum of digits (36).

It is a junction number, because it is equal to n+sod(n) for n = 21902156595 and 21902156604.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21902156641) by changing a digit.

It is a polite number, since it can be written in 191 ways as a sum of consecutive naturals, for example, 509352459 + ... + 509352501.

It is an arithmetic number, because the mean of its divisors is an integer number (85765680).

Almost surely, 2^21902156640 is an apocalyptic number.

21902156640 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 21902156640, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (49401031680).

21902156640 is an abundant number, since it is smaller than the sum of its proper divisors (76899906720).

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

21902156640 is a wasteful number, since it uses less digits than its factorization.

21902156640 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 133 (or 96 counting only the distinct ones).

The product of its (nonzero) digits is 25920, while the sum is 36.

The spelling of 21902156640 in words is "twenty-one billion, nine hundred two million, one hundred fifty-six thousand, six hundred forty".