81992910 has 32 divisors (see below), whose sum is σ = 200973312. Its totient is φ = 21399200.

The previous prime is 81992909. The next prime is 81992927. The reversal of 81992910 is 1929918.

It is a happy number.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 27666 + ... + 30485.

It is an arithmetic number, because the mean of its divisors is an integer number (6280416).

Almost surely, 2^81992910 is an apocalyptic number.

81992910 is an abundant number, since it is smaller than the sum of its proper divisors (118980402).

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

81992910 is a wasteful number, since it uses less digits than its factorization.

81992910 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 58208.

The product of its (nonzero) digits is 11664, while the sum is 39.

The square root of 81992910 is about 9054.9936499149. The cubic root of 81992910 is about 434.4356269258.

The spelling of 81992910 in words is "eighty-one million, nine hundred ninety-two thousand, nine hundred ten".