64890509 has 2 divisors, whose sum is σ = 64890510. Its totient is φ = 64890508.

The previous prime is 64890499. The next prime is 64890557. The reversal of 64890509 is 90509846.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 55920484 + 8970025 = 7478^2 + 2995^2 .

It is a cyclic number.

It is not a de Polignac number, because 64890509 - 2⁴ = 64890493 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (64890559) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 32445254 + 32445255.

It is an arithmetic number, because the mean of its divisors is an integer number (32445255).

Almost surely, 2^64890509 is an apocalyptic number.

It is an amenable number.

64890509 is a deficient number, since it is larger than the sum of its proper divisors (1).

64890509 is an equidigital number, since it uses as much as digits as its factorization.

64890509 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 77760, while the sum is 41.

The square root of 64890509 is about 8055.4645427809. The cubic root of 64890509 is about 401.8466883188.

The spelling of 64890509 in words is "sixty-four million, eight hundred ninety thousand, five hundred nine".