81611216 has 20 divisors (see below), whose sum is σ = 159370752. Its totient is φ = 40483296.

The previous prime is 81611183. The next prime is 81611221. The reversal of 81611216 is 61211618.

It is a hoax number, since the sum of its digits (26) coincides with the sum of the digits of its distinct prime factors.

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 3 ways as a sum of consecutive naturals, for example, 18050 + ... + 22113.

Almost surely, 2^81611216 is an apocalyptic number.

It is an amenable number.

81611216 is a deficient number, since it is larger than the sum of its proper divisors (77759536).

81611216 is a wasteful number, since it uses less digits than its factorization.

81611216 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 40298 (or 40292 counting only the distinct ones).

The product of its digits is 576, while the sum is 26.

The square root of 81611216 is about 9033.8926272123. The cubic root of 81611216 is about 433.7604488288.

The spelling of 81611216 in words is "eighty-one million, six hundred eleven thousand, two hundred sixteen".