81726865 has 16 divisors (see below), whose sum is σ = 108097920. Its totient is φ = 58821120.

The previous prime is 81726851. The next prime is 81726907. The reversal of 81726865 is 56862718.

It is not a de Polignac number, because 81726865 - 2⁵ = 81726833 is a prime.

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, 2325 + ... + 12994.

It is an arithmetic number, because the mean of its divisors is an integer number (6756120).

Almost surely, 2^81726865 is an apocalyptic number.

It is an amenable number.

81726865 is a deficient number, since it is larger than the sum of its proper divisors (26371055).

81726865 is a wasteful number, since it uses less digits than its factorization.

81726865 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 15432.

The product of its digits is 161280, while the sum is 43.

The square root of 81726865 is about 9040.2912010621. The cubic root of 81726865 is about 433.9652421073.

The spelling of 81726865 in words is "eighty-one million, seven hundred twenty-six thousand, eight hundred sixty-five".