81791216 has 40 divisors (see below), whose sum is σ = 180707184. Its totient is φ = 35527680.

The previous prime is 81791209. The next prime is 81791231. The reversal of 81791216 is 61219718.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 8030 + ... + 15101.

Almost surely, 2^81791216 is an apocalyptic number.

It is an amenable number.

81791216 is an abundant number, since it is smaller than the sum of its proper divisors (98915968).

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

81791216 is a wasteful number, since it uses less digits than its factorization.

81791216 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 23169 (or 23163 counting only the distinct ones).

The product of its digits is 6048, while the sum is 35.

The square root of 81791216 is about 9043.8496228100. The cubic root of 81791216 is about 434.0791123380.

The spelling of 81791216 in words is "eighty-one million, seven hundred ninety-one thousand, two hundred sixteen".