64613921 has 2 divisors, whose sum is σ = 64613922. Its totient is φ = 64613920.

The previous prime is 64613881. The next prime is 64613977. The reversal of 64613921 is 12931646.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 44408896 + 20205025 = 6664^2 + 4495^2 .

It is a cyclic number.

It is not a de Polignac number, because 64613921 - 2²² = 60419617 is a prime.

It is a Sophie Germain prime.

It is a Curzon number.

It is not a weakly prime, because it can be changed into another prime (64613221) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 32306960 + 32306961.

It is an arithmetic number, because the mean of its divisors is an integer number (32306961).

Almost surely, 2^64613921 is an apocalyptic number.

It is an amenable number.

64613921 is a deficient number, since it is larger than the sum of its proper divisors (1).

64613921 is an equidigital number, since it uses as much as digits as its factorization.

64613921 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 7776, while the sum is 32.

The square root of 64613921 is about 8038.2784848498. The cubic root of 64613921 is about 401.2749341234.

The spelling of 64613921 in words is "sixty-four million, six hundred thirteen thousand, nine hundred twenty-one".