669158561 has 4 divisors (see below), whose sum is σ = 684720432. Its totient is φ = 653596692.

The previous prime is 669158543. The next prime is 669158563. The reversal of 669158561 is 165851966.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is a cyclic number.

It is not a de Polignac number, because 669158561 - 2²⁶ = 602049697 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (669158563) 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, 7780871 + ... + 7780956.

It is an arithmetic number, because the mean of its divisors is an integer number (171180108).

Almost surely, 2^669158561 is an apocalyptic number.

It is an amenable number.

669158561 is a deficient number, since it is larger than the sum of its proper divisors (15561871).

669158561 is a wasteful number, since it uses less digits than its factorization.

669158561 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 15561870.

The product of its digits is 388800, while the sum is 47.

The square root of 669158561 is about 25868.0992923717. The cubic root of 669158561 is about 874.6675465177.

The spelling of 669158561 in words is "six hundred sixty-nine million, one hundred fifty-eight thousand, five hundred sixty-one".