81249964 has 6 divisors (see below), whose sum is σ = 142187444. Its totient is φ = 40624980.

The previous prime is 81249943. The next prime is 81249979. The reversal of 81249964 is 46994218.

It is a self number, because there is not a number n which added to its sum of digits gives 81249964.

It is an unprimeable number.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10156242 + ... + 10156249.

Almost surely, 2^81249964 is an apocalyptic number.

It is an amenable number.

81249964 is a deficient number, since it is larger than the sum of its proper divisors (60937480).

81249964 is a wasteful number, since it uses less digits than its factorization.

81249964 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 20312495 (or 20312493 counting only the distinct ones).

The product of its digits is 124416, while the sum is 43.

The square root of 81249964 is about 9013.8761917390. The cubic root of 81249964 is about 433.1194887020.

The spelling of 81249964 in words is "eighty-one million, two hundred forty-nine thousand, nine hundred sixty-four".