81206715 has 32 divisors (see below), whose sum is σ = 133747200. Its totient is φ = 42056960.

The previous prime is 81206693. The next prime is 81206737. The reversal of 81206715 is 51760218.

It is an interprime number because it is at equal distance from previous prime (81206693) and next prime (81206737).

It is not a de Polignac number, because 81206715 - 2⁵ = 81206683 is a prime.

It is a super-2 number, since 2×81206715² = 13189061122182450, which contains 22 as substring.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 78250 + ... + 79280.

It is an arithmetic number, because the mean of its divisors is an integer number (4179600).

Almost surely, 2^81206715 is an apocalyptic number.

81206715 is a deficient number, since it is larger than the sum of its proper divisors (52540485).

81206715 is a wasteful number, since it uses less digits than its factorization.

81206715 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1187.

The product of its (nonzero) digits is 3360, while the sum is 30.

The square root of 81206715 is about 9011.4768489965. The cubic root of 81206715 is about 433.0426258602.

The spelling of 81206715 in words is "eighty-one million, two hundred six thousand, seven hundred fifteen".