20639432491964 has 48 divisors (see below), whose sum is σ = 42703795923936. Its totient is φ = 8604743097600.

The previous prime is 20639432491949. The next prime is 20639432491973. The reversal of 20639432491964 is 46919423493602.

It is a junction number, because it is equal to n+sod(n) for n = 20639432491897 and 20639432491906.

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (23) of ones.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 114823967 + ... + 115003574.

It is an arithmetic number, because the mean of its divisors is an integer number (889662415082).

Almost surely, 2^{20639432491964} is an apocalyptic number.

It is an amenable number.

20639432491964 is an abundant number, since it is smaller than the sum of its proper divisors (22064363431972).

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

20639432491964 is a wasteful number, since it uses less digits than its factorization.

20639432491964 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 229827726 (or 229827724 counting only the distinct ones).

The product of its (nonzero) digits is 60466176, while the sum is 62.

The spelling of 20639432491964 in words is "twenty trillion, six hundred thirty-nine billion, four hundred thirty-two million, four hundred ninety-one thousand, nine hundred sixty-four".