64866521 has 2 divisors, whose sum is σ = 64866522. Its totient is φ = 64866520.

The previous prime is 64866517. The next prime is 64866553. The reversal of 64866521 is 12566846.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 64320400 + 546121 = 8020^2 + 739^2 .

It is a cyclic number.

It is not a de Polignac number, because 64866521 - 2² = 64866517 is a prime.

It is not a weakly prime, because it can be changed into another prime (64866511) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 32433260 + 32433261.

It is an arithmetic number, because the mean of its divisors is an integer number (32433261).

Almost surely, 2^64866521 is an apocalyptic number.

It is an amenable number.

64866521 is a deficient number, since it is larger than the sum of its proper divisors (1).

64866521 is an equidigital number, since it uses as much as digits as its factorization.

64866521 is an evil number, because the sum of its binary digits is even.

The product of its digits is 69120, while the sum is 38.

The square root of 64866521 is about 8053.9754779860. The cubic root of 64866521 is about 401.7971654812.

The spelling of 64866521 in words is "sixty-four million, eight hundred sixty-six thousand, five hundred twenty-one".