81290916 has 36 divisors (see below), whose sum is σ = 234841152. Its totient is φ = 23225904.

The previous prime is 81290893. The next prime is 81290927. The reversal of 81290916 is 61909218.

It is a tau number, because it is divible by the number of its divisors (36).

It is a Harshad number since it is a multiple of its sum of digits (36).

It is an unprimeable number.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 161040 + ... + 161543.

Almost surely, 2^81290916 is an apocalyptic number.

It is an amenable number.

81290916 is an abundant number, since it is smaller than the sum of its proper divisors (153550236).

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

81290916 is a wasteful number, since it uses less digits than its factorization.

81290916 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 322600 (or 322595 counting only the distinct ones).

The product of its (nonzero) digits is 7776, while the sum is 36.

The square root of 81290916 is about 9016.1475143212. The cubic root of 81290916 is about 433.1922441400.

The spelling of 81290916 in words is "eighty-one million, two hundred ninety thousand, nine hundred sixteen".