64856521 has 2 divisors, whose sum is σ = 64856522. Its totient is φ = 64856520.

The previous prime is 64856509. The next prime is 64856593. The reversal of 64856521 is 12565846.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 32775625 + 32080896 = 5725^2 + 5664^2 .

It is a cyclic number.

It is not a de Polignac number, because 64856521 - 2¹⁵ = 64823753 is a prime.

It is not a weakly prime, because it can be changed into another prime (64856501) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 32428260 + 32428261.

It is an arithmetic number, because the mean of its divisors is an integer number (32428261).

Almost surely, 2^64856521 is an apocalyptic number.

It is an amenable number.

64856521 is a deficient number, since it is larger than the sum of its proper divisors (1).

64856521 is an equidigital number, since it uses as much as digits as its factorization.

64856521 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 57600, while the sum is 37.

The square root of 64856521 is about 8053.3546426319. The cubic root of 64856521 is about 401.7765170374.

The spelling of 64856521 in words is "sixty-four million, eight hundred fifty-six thousand, five hundred twenty-one".