81894508 has 18 divisors (see below), whose sum is σ = 152243756. Its totient is φ = 38538048.

The previous prime is 81894499. The next prime is 81894511. The reversal of 81894508 is 80549818.

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 5 ways as a sum of consecutive naturals, for example, 34266 + ... + 36577.

Almost surely, 2^81894508 is an apocalyptic number.

It is an amenable number.

81894508 is a deficient number, since it is larger than the sum of its proper divisors (70349248).

81894508 is a wasteful number, since it uses less digits than its factorization.

81894508 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 70881 (or 70862 counting only the distinct ones).

The product of its (nonzero) digits is 92160, while the sum is 43.

The square root of 81894508 is about 9049.5584422667. The cubic root of 81894508 is about 434.2617645454.

The spelling of 81894508 in words is "eighty-one million, eight hundred ninety-four thousand, five hundred eight".