81993607910 has 32 divisors (see below), whose sum is σ = 152695951200. Its totient is φ = 31662722560.

The previous prime is 81993607849. The next prime is 81993607951. The reversal of 81993607910 is 1970639918.

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 15 ways as a sum of consecutive naturals, for example, 4561721 + ... + 4579659.

It is an arithmetic number, because the mean of its divisors is an integer number (4771748475).

Almost surely, 2^81993607910 is an apocalyptic number.

81993607910 is a deficient number, since it is larger than the sum of its proper divisors (70702343290).

81993607910 is a wasteful number, since it uses less digits than its factorization.

81993607910 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 33736.

The product of its (nonzero) digits is 734832, while the sum is 53.

The spelling of 81993607910 in words is "eighty-one billion, nine hundred ninety-three million, six hundred seven thousand, nine hundred ten".