20921569964 has 12 divisors (see below), whose sum is σ = 37053865464. Its totient is φ = 10334751264.

The previous prime is 20921569939. The next prime is 20921569967. The reversal of 20921569964 is 46996512902.

It is a happy number.

It is a super-2 number, since 2×20921569964² (a number of 21 digits) contains 22 as substring.

It is not an unprimeable number, because it can be changed into a prime (20921569967) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 31508057 + ... + 31508720.

It is an arithmetic number, because the mean of its divisors is an integer number (3087822122).

Almost surely, 2^20921569964 is an apocalyptic number.

It is an amenable number.

20921569964 is a deficient number, since it is larger than the sum of its proper divisors (16132295500).

20921569964 is a wasteful number, since it uses less digits than its factorization.

20921569964 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 63016864 (or 63016862 counting only the distinct ones).

The product of its (nonzero) digits is 2099520, while the sum is 53.

The spelling of 20921569964 in words is "twenty billion, nine hundred twenty-one million, five hundred sixty-nine thousand, nine hundred sixty-four".