81137910 has 32 divisors (see below), whose sum is σ = 222550272. Its totient is φ = 18545760.

The previous prime is 81137909. The next prime is 81137971. The reversal of 81137910 is 1973118.

It is a Harshad number since it is a multiple of its sum of digits (30).

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 192976 + ... + 193395.

It is an arithmetic number, because the mean of its divisors is an integer number (6954696).

Almost surely, 2^81137910 is an apocalyptic number.

81137910 is an abundant number, since it is smaller than the sum of its proper divisors (141412362).

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

81137910 is a wasteful number, since it uses less digits than its factorization.

81137910 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 386388.

The product of its (nonzero) digits is 1512, while the sum is 30.

The square root of 81137910 is about 9007.6584082657. The cubic root of 81137910 is about 432.9202882066.

The spelling of 81137910 in words is "eighty-one million, one hundred thirty-seven thousand, nine hundred ten".