64128509 has 2 divisors, whose sum is σ = 64128510. Its totient is φ = 64128508.

The previous prime is 64128499. The next prime is 64128563. The reversal of 64128509 is 90582146.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 40576900 + 23551609 = 6370^2 + 4853^2 .

It is a cyclic number.

It is not a de Polignac number, because 64128509 - 2¹² = 64124413 is a prime.

It is a super-2 number, since 2×64128509² = 8224931333126162, which contains 22 as substring.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (64128809) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 32064254 + 32064255.

It is an arithmetic number, because the mean of its divisors is an integer number (32064255).

Almost surely, 2^64128509 is an apocalyptic number.

It is an amenable number.

64128509 is a deficient number, since it is larger than the sum of its proper divisors (1).

64128509 is an equidigital number, since it uses as much as digits as its factorization.

64128509 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 17280, while the sum is 35.

The square root of 64128509 is about 8008.0277846671. The cubic root of 64128509 is about 400.2675480885.

The spelling of 64128509 in words is "sixty-four million, one hundred twenty-eight thousand, five hundred nine".