21245037156 has 192 divisors, whose sum is σ = 67081996800. Its totient is φ = 5676023808.

The previous prime is 21245037127. The next prime is 21245037179. The reversal of 21245037156 is 65173054212.

21245037156 is a `hidden beast` number, since 21 + 2 + 450 + 37 + 156 = 666.

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

It is a self number, because there is not a number n which added to its sum of digits gives 21245037156.

It is an unprimeable number.

It is a polite number, since it can be written in 63 ways as a sum of consecutive naturals, for example, 2012500 + ... + 2023028.

It is an arithmetic number, because the mean of its divisors is an integer number (349385400).

Almost surely, 2^21245037156 is an apocalyptic number.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 21245037156, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (33540998400).

21245037156 is an abundant number, since it is smaller than the sum of its proper divisors (45836959644).

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

21245037156 is a wasteful number, since it uses less digits than its factorization.

21245037156 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 10723 (or 10715 counting only the distinct ones).

The product of its (nonzero) digits is 50400, while the sum is 36.

The spelling of 21245037156 in words is "twenty-one billion, two hundred forty-five million, thirty-seven thousand, one hundred fifty-six".