669508591 has 4 divisors (see below), whose sum is σ = 670623184. Its totient is φ = 668394000.

The previous prime is 669508589. The next prime is 669508597. The reversal of 669508591 is 195805966.

It is a semiprime because it is the product of two primes.

It is a cyclic number.

It is not a de Polignac number, because 669508591 - 2¹ = 669508589 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (669508597) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 556395 + ... + 557596.

It is an arithmetic number, because the mean of its divisors is an integer number (167655796).

Almost surely, 2^669508591 is an apocalyptic number.

669508591 is a deficient number, since it is larger than the sum of its proper divisors (1114593).

669508591 is a wasteful number, since it uses less digits than its factorization.

669508591 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1114592.

The product of its (nonzero) digits is 583200, while the sum is 49.

The square root of 669508591 is about 25874.8640769377. The cubic root of 669508591 is about 874.8200298162.

The spelling of 669508591 in words is "six hundred sixty-nine million, five hundred eight thousand, five hundred ninety-one".