81815012 has 12 divisors (see below), whose sum is σ = 143502576. Its totient is φ = 40814280.

The previous prime is 81815011. The next prime is 81815021. The reversal of 81815012 is 21051818.

It is not an unprimeable number, because it can be changed into a prime (81815011) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 21314 + ... + 24857.

It is an arithmetic number, because the mean of its divisors is an integer number (11958548).

Almost surely, 2^81815012 is an apocalyptic number.

It is an amenable number.

81815012 is a deficient number, since it is larger than the sum of its proper divisors (61687564).

81815012 is a wasteful number, since it uses less digits than its factorization.

81815012 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 46618 (or 46616 counting only the distinct ones).

The product of its (nonzero) digits is 640, while the sum is 26.

The square root of 81815012 is about 9045.1651173431. The cubic root of 81815012 is about 434.1212046534.

The spelling of 81815012 in words is "eighty-one million, eight hundred fifteen thousand, twelve".