81858866 has 16 divisors (see below), whose sum is σ = 126406656. Its totient is φ = 39737376.

The previous prime is 81858857. The next prime is 81858877. The reversal of 81858866 is 66885818.

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, 8510 + ... + 15366.

It is an arithmetic number, because the mean of its divisors is an integer number (7900416).

Almost surely, 2^81858866 is an apocalyptic number.

81858866 is a deficient number, since it is larger than the sum of its proper divisors (44547790).

81858866 is a wasteful number, since it uses less digits than its factorization.

81858866 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 7033.

The product of its digits is 737280, while the sum is 50.

The square root of 81858866 is about 9047.5889606016. The cubic root of 81858866 is about 434.1987558278.

The spelling of 81858866 in words is "eighty-one million, eight hundred fifty-eight thousand, eight hundred sixty-six".