20157209856 has 576 divisors, whose sum is σ = 71582515200. Its totient is φ = 5474304000.

The previous prime is 20157209851. The next prime is 20157209881. The reversal of 20157209856 is 65890275102.

20157209856 is a `hidden beast` number, since 20 + 1 + 572 + 0 + 9 + 8 + 56 = 666.

It is a tau number, because it is divible by the number of its divisors (576).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (20157209851) by changing a digit.

It is a polite number, since it can be written in 63 ways as a sum of consecutive naturals, for example, 133491381 + ... + 133491531.

It is an arithmetic number, because the mean of its divisors is an integer number (124275200).

Almost surely, 2^20157209856 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 20157209856, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (35791257600).

20157209856 is an abundant number, since it is smaller than the sum of its proper divisors (51425305344).

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

20157209856 is a wasteful number, since it uses less digits than its factorization.

20157209856 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 303 (or 283 counting only the distinct ones).

The product of its (nonzero) digits is 302400, while the sum is 45.

The spelling of 20157209856 in words is "twenty billion, one hundred fifty-seven million, two hundred nine thousand, eight hundred fifty-six".