81964331884 has 24 divisors (see below), whose sum is σ = 146310167808. Its totient is φ = 40163185920.

The previous prime is 81964331789. The next prime is 81964331923. The reversal of 81964331884 is 48813346918.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 32652 + ... + 406195.

It is an arithmetic number, because the mean of its divisors is an integer number (6096256992).

Almost surely, 2^81964331884 is an apocalyptic number.

It is an amenable number.

81964331884 is a deficient number, since it is larger than the sum of its proper divisors (64345835924).

81964331884 is a wasteful number, since it uses less digits than its factorization.

81964331884 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 439785 (or 439783 counting only the distinct ones).

The product of its digits is 3981312, while the sum is 55.

The spelling of 81964331884 in words is "eighty-one billion, nine hundred sixty-four million, three hundred thirty-one thousand, eight hundred eighty-four".