81308866 has 16 divisors (see below), whose sum is σ = 132811200. Its totient is φ = 37186128.

The previous prime is 81308849. The next prime is 81308873. The reversal of 81308866 is 66880318.

It is a super-2 number, since 2×81308866² = 13222263380411912, which contains 22 as substring.

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, 35790 + ... + 37993.

It is an arithmetic number, because the mean of its divisors is an integer number (8300700).

Almost surely, 2^81308866 is an apocalyptic number.

81308866 is a deficient number, since it is larger than the sum of its proper divisors (51502334).

81308866 is a wasteful number, since it uses less digits than its factorization.

81308866 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 73833.

The product of its (nonzero) digits is 55296, while the sum is 40.

The square root of 81308866 is about 9017.1428956183. The cubic root of 81308866 is about 433.2241264581.

The spelling of 81308866 in words is "eighty-one million, three hundred eight thousand, eight hundred sixty-six".