81816715 has 16 divisors (see below), whose sum is σ = 100113408. Its totient is φ = 64174176.

The previous prime is 81816703. The next prime is 81816737. The reversal of 81816715 is 51761818.

It is a cyclic number.

It is not a de Polignac number, because 81816715 - 2¹³ = 81808523 is a prime.

It is a Duffinian number.

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, 94374 + ... + 95236.

It is an arithmetic number, because the mean of its divisors is an integer number (6257088).

Almost surely, 2^81816715 is an apocalyptic number.

81816715 is a deficient number, since it is larger than the sum of its proper divisors (18296693).

81816715 is a wasteful number, since it uses less digits than its factorization.

81816715 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1218.

The product of its digits is 13440, while the sum is 37.

The square root of 81816715 is about 9045.2592555438. The cubic root of 81816715 is about 434.1242167465.

The spelling of 81816715 in words is "eighty-one million, eight hundred sixteen thousand, seven hundred fifteen".