81349866 has 32 divisors (see below), whose sum is σ = 194685120. Its totient is φ = 25030512.

The previous prime is 81349847. The next prime is 81349871. The reversal of 81349866 is 66894318.

It is an unprimeable number.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 57240 + ... + 58643.

It is an arithmetic number, because the mean of its divisors is an integer number (6083910).

Almost surely, 2^81349866 is an apocalyptic number.

81349866 is an abundant number, since it is smaller than the sum of its proper divisors (113335254).

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

81349866 is a wasteful number, since it uses less digits than its factorization.

81349866 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 115907 (or 115901 counting only the distinct ones).

The product of its digits is 248832, while the sum is 45.

The square root of 81349866 is about 9019.4160564861. The cubic root of 81349866 is about 433.2969319850.

It can be divided in two parts, 81349 and 866, that added together give a triangular number (82215 = T₄₀₅).

The spelling of 81349866 in words is "eighty-one million, three hundred forty-nine thousand, eight hundred sixty-six".