20561556474 has 48 divisors (see below), whose sum is σ = 47193269760. Its totient is φ = 6447588480.

The previous prime is 20561556443. The next prime is 20561556479. The reversal of 20561556474 is 47465516502.

20561556474 is a `hidden beast` number, since 2 + 0 + 5 + 6 + 15 + 564 + 74 = 666.

It is not an unprimeable number, because it can be changed into a prime (20561556479) 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, 670129 + ... + 700139.

It is an arithmetic number, because the mean of its divisors is an integer number (983193120).

Almost surely, 2^20561556474 is an apocalyptic number.

20561556474 is an abundant number, since it is smaller than the sum of its proper divisors (26631713286).

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

20561556474 is a wasteful number, since it uses less digits than its factorization.

20561556474 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 32275 (or 32272 counting only the distinct ones).

The product of its (nonzero) digits is 1008000, while the sum is 45.

The spelling of 20561556474 in words is "twenty billion, five hundred sixty-one million, five hundred fifty-six thousand, four hundred seventy-four".