81906168 has 48 divisors (see below), whose sum is σ = 207996840. Its totient is φ = 26877760.

The previous prime is 81906113. The next prime is 81906193. The reversal of 81906168 is 86160918.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 120646 + ... + 121322.

Almost surely, 2^81906168 is an apocalyptic number.

It is an amenable number.

81906168 is an abundant number, since it is smaller than the sum of its proper divisors (126090672).

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

81906168 is a wasteful number, since it uses less digits than its factorization.

81906168 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 828 (or 753 counting only the distinct ones).

The product of its (nonzero) digits is 20736, while the sum is 39.

The square root of 81906168 is about 9050.2026496648. The cubic root of 81906168 is about 434.2823733832.

The spelling of 81906168 in words is "eighty-one million, nine hundred six thousand, one hundred sixty-eight".