64517561 has 2 divisors, whose sum is σ = 64517562. Its totient is φ = 64517560.

The previous prime is 64517429. The next prime is 64517573. The reversal of 64517561 is 16571546.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 52649536 + 11868025 = 7256^2 + 3445^2 .

It is a cyclic number.

It is not a de Polignac number, because 64517561 - 2¹⁰ = 64516537 is a prime.

It is not a weakly prime, because it can be changed into another prime (64517581) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 32258780 + 32258781.

It is an arithmetic number, because the mean of its divisors is an integer number (32258781).

Almost surely, 2^64517561 is an apocalyptic number.

It is an amenable number.

64517561 is a deficient number, since it is larger than the sum of its proper divisors (1).

64517561 is an equidigital number, since it uses as much as digits as its factorization.

64517561 is an evil number, because the sum of its binary digits is even.

The product of its digits is 25200, while the sum is 35.

The square root of 64517561 is about 8032.2824278034. The cubic root of 64517561 is about 401.0753585029.

The spelling of 64517561 in words is "sixty-four million, five hundred seventeen thousand, five hundred sixty-one".