81916353 has 80 divisors (see below), whose sum is σ = 142179840. Its totient is φ = 46656000.

The previous prime is 81916349. The next prime is 81916357. The reversal of 81916353 is 35361918.

It is a happy number.

81916353 is a `hidden beast` number, since 8 + 19 + 1 + 635 + 3 = 666.

It is an interprime number because it is at equal distance from previous prime (81916349) and next prime (81916357).

It is not a de Polignac number, because 81916353 - 2² = 81916349 is a prime.

It is a Smith number, since the sum of its digits (36) coincides with the sum of the digits of its prime factors.

Its product of digits (19440) is a multiple of the sum of its prime factors (180).

It is not an unprimeable number, because it can be changed into a prime (81916357) by changing a digit.

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 79 ways as a sum of consecutive naturals, for example, 811003 + ... + 811103.

It is an arithmetic number, because the mean of its divisors is an integer number (1777248).

Almost surely, 2^81916353 is an apocalyptic number.

It is an amenable number.

81916353 is a deficient number, since it is larger than the sum of its proper divisors (60263487).

81916353 is a wasteful number, since it uses less digits than its factorization.

81916353 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 180 (or 171 counting only the distinct ones).

The product of its digits is 19440, while the sum is 36.

The square root of 81916353 is about 9050.7653267555. The cubic root of 81916353 is about 434.3003735849.

The spelling of 81916353 in words is "eighty-one million, nine hundred sixteen thousand, three hundred fifty-three".