81166616 has 8 divisors (see below), whose sum is σ = 152187420. Its totient is φ = 40583304.

The previous prime is 81166607. The next prime is 81166633. The reversal of 81166616 is 61666118.

It is a tau number, because it is divible by the number of its divisors (8).

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 5072906 + ... + 5072921.

Almost surely, 2^81166616 is an apocalyptic number.

It is an amenable number.

81166616 is a deficient number, since it is larger than the sum of its proper divisors (71020804).

81166616 is a wasteful number, since it uses less digits than its factorization.

81166616 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 10145833 (or 10145829 counting only the distinct ones).

The product of its digits is 10368, while the sum is 35.

The square root of 81166616 is about 9009.2516892359. The cubic root of 81166616 is about 432.9713368656.

The spelling of 81166616 in words is "eighty-one million, one hundred sixty-six thousand, six hundred sixteen".