65312721 has 12 divisors (see below), whose sum is σ = 94677648. Its totient is φ = 43386264.

The previous prime is 65312717. The next prime is 65312773. The reversal of 65312721 is 12721356.

It is a happy number.

65312721 is a `hidden beast` number, since 653 + 1 + 2 + 7 + 2 + 1 = 666.

It is not a de Polignac number, because 65312721 - 2² = 65312717 is a prime.

It is not an unprimeable number, because it can be changed into a prime (65312701) by changing a digit.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 10275 + ... + 15368.

It is an arithmetic number, because the mean of its divisors is an integer number (7889804).

Almost surely, 2^65312721 is an apocalyptic number.

It is an amenable number.

65312721 is a deficient number, since it is larger than the sum of its proper divisors (29364927).

65312721 is a wasteful number, since it uses less digits than its factorization.

65312721 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 25932 (or 25929 counting only the distinct ones).

The product of its digits is 2520, while the sum is 27.

The square root of 65312721 is about 8081.6286106205. The cubic root of 65312721 is about 402.7163473044.

The spelling of 65312721 in words is "sixty-five million, three hundred twelve thousand, seven hundred twenty-one".