20561670520 has 32 divisors (see below), whose sum is σ = 46271470320. Its totient is φ = 8223297280.

The previous prime is 20561670463. The next prime is 20561670523. The reversal of 20561670520 is 2507616502.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (20561670523) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 220044 + ... + 299236.

Almost surely, 2^20561670520 is an apocalyptic number.

20561670520 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

20561670520 is an abundant number, since it is smaller than the sum of its proper divisors (25709799800).

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

20561670520 is a wasteful number, since it uses less digits than its factorization.

20561670520 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 85695 (or 85691 counting only the distinct ones).

The product of its (nonzero) digits is 25200, while the sum is 34.

The spelling of 20561670520 in words is "twenty billion, five hundred sixty-one million, six hundred seventy thousand, five hundred twenty".