64764721 has 6 divisors (see below), whose sum is σ = 75338610. Its totient is φ = 55512576.

The previous prime is 64764703. The next prime is 64764767. The reversal of 64764721 is 12746746.

It can be written as a sum of positive squares in only one way, i.e., 42107121 + 22657600 = 6489^2 + 4760^2 .

It is not a de Polignac number, because 64764721 - 2⁷ = 64764593 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (64767721) by changing a digit.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 660816 + ... + 660913.

It is an arithmetic number, because the mean of its divisors is an integer number (12556435).

Almost surely, 2^64764721 is an apocalyptic number.

It is an amenable number.

64764721 is a deficient number, since it is larger than the sum of its proper divisors (10573889).

64764721 is a wasteful number, since it uses less digits than its factorization.

64764721 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1321743 (or 1321736 counting only the distinct ones).

The product of its digits is 56448, while the sum is 37.

The square root of 64764721 is about 8047.6531361634. The cubic root of 64764721 is about 401.5868650732.

The spelling of 64764721 in words is "sixty-four million, seven hundred sixty-four thousand, seven hundred twenty-one".