665390563 has 2 divisors, whose sum is σ = 665390564. Its totient is φ = 665390562.

The previous prime is 665390543. The next prime is 665390617. The reversal of 665390563 is 365093566.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 665390563 - 2²⁵ = 631836131 is a prime.

It is not a weakly prime, because it can be changed into another prime (665390503) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 332695281 + 332695282.

It is an arithmetic number, because the mean of its divisors is an integer number (332695282).

Almost surely, 2^665390563 is an apocalyptic number.

665390563 is a deficient number, since it is larger than the sum of its proper divisors (1).

665390563 is an equidigital number, since it uses as much as digits as its factorization.

665390563 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 437400, while the sum is 43.

The square root of 665390563 is about 25795.1654966585. The cubic root of 665390563 is about 873.0227190971.

The spelling of 665390563 in words is "six hundred sixty-five million, three hundred ninety thousand, five hundred sixty-three".