64513921 has 2 divisors, whose sum is σ = 64513922. Its totient is φ = 64513920.

The previous prime is 64513913. The next prime is 64513979. The reversal of 64513921 is 12931546.

64513921 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 32433025 + 32080896 = 5695^2 + 5664^2 .

It is a cyclic number.

It is not a de Polignac number, because 64513921 - 2³ = 64513913 is a prime.

It is not a weakly prime, because it can be changed into another prime (64513021) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 32256960 + 32256961.

It is an arithmetic number, because the mean of its divisors is an integer number (32256961).

Almost surely, 2^64513921 is an apocalyptic number.

It is an amenable number.

64513921 is a deficient number, since it is larger than the sum of its proper divisors (1).

64513921 is an equidigital number, since it uses as much as digits as its factorization.

64513921 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 6480, while the sum is 31.

The square root of 64513921 is about 8032.0558389493. The cubic root of 64513921 is about 401.0678156378.

The spelling of 64513921 in words is "sixty-four million, five hundred thirteen thousand, nine hundred twenty-one".