669412129 has 3 divisors (see below), whose sum is σ = 669438003. Its totient is φ = 669386256.

The previous prime is 669412097. The next prime is 669412147. The reversal of 669412129 is 921214966.

The square root of 669412129 is 25873.

It is a perfect power (a square), and thus also a powerful number.

It is a semiprime because it is the product of two primes, and also a brilliant number, because the two primes have the same length.

It can be written as a sum of positive squares in only one way, i.e., 321664225 + 347747904 = 17935^2 + 18648^2 .

It is not a de Polignac number, because 669412129 - 2⁵ = 669412097 is a prime.

It is a super-2 number, since 2×669412129² = 896225196904625282, which contains 22 as substring.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 669412091 and 669412100.

It is not an unprimeable number, because it can be changed into a prime (669412169) by changing a digit.

It is a polite number, since it can be written in 2 ways as a sum of consecutive naturals, for example, 12937 + ... + 38809.

It is an arithmetic number, because the mean of its divisors is an integer number (223146001).

Almost surely, 2^669412129 is an apocalyptic number.

669412129 is the 25873-rd square number.

669412129 is the 12937-th centered octagonal number.

It is an amenable number.

669412129 is a deficient number, since it is larger than the sum of its proper divisors (25874).

669412129 is an frugal number, since it uses more digits than its factorization.

669412129 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 51746 (or 25873 counting only the distinct ones).

The product of its digits is 46656, while the sum is 40.

The cubic root of 669412129 is about 874.7780134557.

Multiplying 669412129 by its product of digits (46656), we get a square (31232092290624 = 5588568²).

The spelling of 669412129 in words is "six hundred sixty-nine million, four hundred twelve thousand, one hundred twenty-nine".