20915574021 has 6 divisors (see below), whose sum is σ = 30211384710. Its totient is φ = 13943716008.

The previous prime is 20915574007. The next prime is 20915574041. The reversal of 20915574021 is 12047551902.

It can be written as a sum of positive squares in only one way, i.e., 20796524100 + 119049921 = 144210^2 + 10911^2 .

It is not a de Polignac number, because 20915574021 - 2⁶ = 20915573957 is a prime.

It is a super-2 number, since 2×20915574021² (a number of 21 digits) contains 22 as substring.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (20915574041) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 1161976326 + ... + 1161976343.

It is an arithmetic number, because the mean of its divisors is an integer number (5035230785).

Almost surely, 2^20915574021 is an apocalyptic number.

It is an amenable number.

20915574021 is a deficient number, since it is larger than the sum of its proper divisors (9295810689).

20915574021 is a wasteful number, since it uses less digits than its factorization.

20915574021 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2323952675 (or 2323952672 counting only the distinct ones).

The product of its (nonzero) digits is 25200, while the sum is 36.

The spelling of 20915574021 in words is "twenty billion, nine hundred fifteen million, five hundred seventy-four thousand, twenty-one".