81906456 has 32 divisors (see below), whose sum is σ = 210302640. Its totient is φ = 26563968.

The previous prime is 81906449. The next prime is 81906481. The reversal of 81906456 is 65460918.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 45231 + ... + 47006.

Almost surely, 2^81906456 is an apocalyptic number.

It is an amenable number.

81906456 is an abundant number, since it is smaller than the sum of its proper divisors (128396184).

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

81906456 is a wasteful number, since it uses less digits than its factorization.

81906456 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 92283 (or 92279 counting only the distinct ones).

The product of its (nonzero) digits is 51840, while the sum is 39.

The square root of 81906456 is about 9050.2185608967. The cubic root of 81906456 is about 434.2828823932.

The spelling of 81906456 in words is "eighty-one million, nine hundred six thousand, four hundred fifty-six".