64648721 has 2 divisors, whose sum is σ = 64648722. Its totient is φ = 64648720.

The previous prime is 64648709. The next prime is 64648741. The reversal of 64648721 is 12784646.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 50481025 + 14167696 = 7105^2 + 3764^2 .

It is a cyclic number.

It is not a de Polignac number, because 64648721 - 2¹⁸ = 64386577 is a prime.

It is a Chen prime.

It is not a weakly prime, because it can be changed into another prime (64648741) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 32324360 + 32324361.

It is an arithmetic number, because the mean of its divisors is an integer number (32324361).

Almost surely, 2^64648721 is an apocalyptic number.

It is an amenable number.

64648721 is a deficient number, since it is larger than the sum of its proper divisors (1).

64648721 is an equidigital number, since it uses as much as digits as its factorization.

64648721 is an evil number, because the sum of its binary digits is even.

The product of its digits is 64512, while the sum is 38.

The square root of 64648721 is about 8040.4428360632. The cubic root of 64648721 is about 401.3469612307.

The spelling of 64648721 in words is "sixty-four million, six hundred forty-eight thousand, seven hundred twenty-one".