669618121 has 4 divisors (see below), whose sum is σ = 704861200. Its totient is φ = 634375044.

The previous prime is 669618029. The next prime is 669618133. The reversal of 669618121 is 121816966.

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 669618121 - 2¹³ = 669609929 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (669618161) 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, 17621511 + ... + 17621548.

It is an arithmetic number, because the mean of its divisors is an integer number (176215300).

Almost surely, 2^669618121 is an apocalyptic number.

It is an amenable number.

669618121 is a deficient number, since it is larger than the sum of its proper divisors (35243079).

669618121 is a wasteful number, since it uses less digits than its factorization.

669618121 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 35243078.

The product of its digits is 31104, while the sum is 40.

The square root of 669618121 is about 25876.9805232373. The cubic root of 669618121 is about 874.8677333679.

The spelling of 669618121 in words is "six hundred sixty-nine million, six hundred eighteen thousand, one hundred twenty-one".