64890557 has 2 divisors, whose sum is σ = 64890558. Its totient is φ = 64890556.

The previous prime is 64890509. The next prime is 64890559. The reversal of 64890557 is 75509846.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 61246276 + 3644281 = 7826^2 + 1909^2 .

It is a cyclic number.

It is not a de Polignac number, because 64890557 - 2⁶ = 64890493 is a prime.

Together with 64890559, it forms a pair of twin primes.

It is a Chen 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 pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 32445278 + 32445279.

It is an arithmetic number, because the mean of its divisors is an integer number (32445279).

Almost surely, 2^64890557 is an apocalyptic number.

It is an amenable number.

64890557 is a deficient number, since it is larger than the sum of its proper divisors (1).

64890557 is an equidigital number, since it uses as much as digits as its factorization.

64890557 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 302400, while the sum is 44.

The square root of 64890557 is about 8055.4675221243. The cubic root of 64890557 is about 401.8467874018.

The spelling of 64890557 in words is "sixty-four million, eight hundred ninety thousand, five hundred fifty-seven".