81581208 has 32 divisors (see below), whose sum is σ = 204294960. Its totient is φ = 27148160.

The previous prime is 81581197. The next prime is 81581233. The reversal of 81581208 is 80218518.

It is a hoax number, since the sum of its digits (33) 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 7 ways as a sum of consecutive naturals, for example, 13738 + ... + 18758.

Almost surely, 2^81581208 is an apocalyptic number.

It is an amenable number.

81581208 is an abundant number, since it is smaller than the sum of its proper divisors (122713752).

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

81581208 is a wasteful number, since it uses less digits than its factorization.

81581208 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 5707 (or 5703 counting only the distinct ones).

The product of its (nonzero) digits is 5120, while the sum is 33.

The square root of 81581208 is about 9032.2316179336. The cubic root of 81581208 is about 433.7072785259.

The spelling of 81581208 in words is "eighty-one million, five hundred eighty-one thousand, two hundred eight".