81639048532 has 24 divisors (see below), whose sum is σ = 153885116000. Its totient is φ = 37771798176.

The previous prime is 81639048529. The next prime is 81639048577. The reversal of 81639048532 is 23584093618.

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 12487407 + ... + 12493942.

Almost surely, 2^81639048532 is an apocalyptic number.

It is an amenable number.

81639048532 is a deficient number, since it is larger than the sum of its proper divisors (72246067468).

81639048532 is a wasteful number, since it uses less digits than its factorization.

81639048532 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 24981415 (or 24981413 counting only the distinct ones).

The product of its (nonzero) digits is 1244160, while the sum is 49.

The spelling of 81639048532 in words is "eighty-one billion, six hundred thirty-nine million, forty-eight thousand, five hundred thirty-two".