669725138 has 4 divisors (see below), whose sum is σ = 1004587710. Its totient is φ = 334862568.

The previous prime is 669725113. The next prime is 669725153. The reversal of 669725138 is 831527966.

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

It can be written as a sum of positive squares in only one way, i.e., 658589569 + 11135569 = 25663^2 + 3337^2 .

It is a junction number, because it is equal to n+sod(n) for n = 669725092 and 669725101.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 167431283 + ... + 167431286.

Almost surely, 2^669725138 is an apocalyptic number.

669725138 is a deficient number, since it is larger than the sum of its proper divisors (334862572).

669725138 is a wasteful number, since it uses less digits than its factorization.

669725138 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 334862571.

The product of its digits is 544320, while the sum is 47.

The square root of 669725138 is about 25879.0482437048. The cubic root of 669725138 is about 874.9143374098.

The spelling of 669725138 in words is "six hundred sixty-nine million, seven hundred twenty-five thousand, one hundred thirty-eight".