65723991 has 16 divisors (see below), whose sum is σ = 88967424. Its totient is φ = 43153344.

The previous prime is 65723981. The next prime is 65724013. The reversal of 65723991 is 19932756.

It is not a de Polignac number, because 65723991 - 2⁷ = 65723863 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (65723981) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 69675 + ... + 70611.

It is an arithmetic number, because the mean of its divisors is an integer number (5560464).

Almost surely, 2^65723991 is an apocalyptic number.

65723991 is a deficient number, since it is larger than the sum of its proper divisors (23243433).

65723991 is a wasteful number, since it uses less digits than its factorization.

65723991 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1270.

The product of its digits is 102060, while the sum is 42.

The square root of 65723991 is about 8107.0334278329. The cubic root of 65723991 is about 403.5598722056.

The spelling of 65723991 in words is "sixty-five million, seven hundred twenty-three thousand, nine hundred ninety-one".