81908316 has 72 divisors (see below), whose sum is σ = 249092480. Its totient is φ = 22169376.

The previous prime is 81908311. The next prime is 81908339. The reversal of 81908316 is 61380918.

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

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (81908311) 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 23 ways as a sum of consecutive naturals, for example, 3766 + ... + 13341.

Almost surely, 2^81908316 is an apocalyptic number.

It is an amenable number.

81908316 is an abundant number, since it is smaller than the sum of its proper divisors (167184164).

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

81908316 is a wasteful number, since it uses less digits than its factorization.

81908316 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 17143 (or 17138 counting only the distinct ones).

The product of its (nonzero) digits is 10368, while the sum is 36.

The square root of 81908316 is about 9050.3213202626. The cubic root of 81908316 is about 434.2861697207.

The spelling of 81908316 in words is "eighty-one million, nine hundred eight thousand, three hundred sixteen".