81787331004 has 24 divisors (see below), whose sum is σ = 191656155600. Its totient is φ = 27145436544.

The previous prime is 81787330943. The next prime is 81787331023. The reversal of 81787331004 is 40013378718.

It is a happy number.

It is a congruent number.

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, 14622979 + ... + 14628570.

It is an arithmetic number, because the mean of its divisors is an integer number (7985673150).

Almost surely, 2^81787331004 is an apocalyptic number.

It is an amenable number.

81787331004 is an abundant number, since it is smaller than the sum of its proper divisors (109868824596).

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

81787331004 is a wasteful number, since it uses less digits than its factorization.

81787331004 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 29251789 (or 29251787 counting only the distinct ones).

The product of its (nonzero) digits is 112896, while the sum is 42.

The spelling of 81787331004 in words is "eighty-one billion, seven hundred eighty-seven million, three hundred thirty-one thousand, four".