64791809 has 2 divisors, whose sum is σ = 64791810. Its totient is φ = 64791808.

The previous prime is 64791791. The next prime is 64791833. The reversal of 64791809 is 90819746.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 44289025 + 20502784 = 6655^2 + 4528^2 .

It is a cyclic number.

It is not a de Polignac number, because 64791809 - 2⁸ = 64791553 is a prime.

It is a self number, because there is not a number n which added to its sum of digits gives 64791809.

It is not a weakly prime, because it can be changed into another prime (64791899) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 32395904 + 32395905.

It is an arithmetic number, because the mean of its divisors is an integer number (32395905).

Almost surely, 2^64791809 is an apocalyptic number.

It is an amenable number.

64791809 is a deficient number, since it is larger than the sum of its proper divisors (1).

64791809 is an equidigital number, since it uses as much as digits as its factorization.

64791809 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 108864, while the sum is 44.

The square root of 64791809 is about 8049.3359353427. The cubic root of 64791809 is about 401.6428454927.

The spelling of 64791809 in words is "sixty-four million, seven hundred ninety-one thousand, eight hundred nine".