81642715 has 32 divisors (see below), whose sum is σ = 128586240. Its totient is φ = 48211200.

The previous prime is 81642707. The next prime is 81642719. The reversal of 81642715 is 51724618.

It is not a de Polignac number, because 81642715 - 2³ = 81642707 is a prime.

It is a Smith number, since the sum of its digits (34) coincides with the sum of the digits of its prime factors. Since it is squarefree, it is also a hoax number.

It is not an unprimeable number, because it can be changed into a prime (81642719) by changing a digit.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 1735 + ... + 12895.

It is an arithmetic number, because the mean of its divisors is an integer number (4018320).

Almost surely, 2^81642715 is an apocalyptic number.

81642715 is a deficient number, since it is larger than the sum of its proper divisors (46943525).

81642715 is a wasteful number, since it uses less digits than its factorization.

81642715 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 11203.

The product of its digits is 13440, while the sum is 34.

The square root of 81642715 is about 9035.6358381688. The cubic root of 81642715 is about 433.8162469720.

The spelling of 81642715 in words is "eighty-one million, six hundred forty-two thousand, seven hundred fifteen".