669778506 has 12 divisors (see below), whose sum is σ = 1451186802. Its totient is φ = 223259496.

The previous prime is 669778453. The next prime is 669778541. The reversal of 669778506 is 605877966.

It is a happy number.

669778506 is a `hidden beast` number, since 6 + 69 + 7 + 78 + 506 = 666.

It can be written as a sum of positive squares in only one way, i.e., 411887025 + 257891481 = 20295^2 + 16059^2 .

It is a Curzon number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 18604941 + ... + 18604976.

Almost surely, 2^669778506 is an apocalyptic number.

669778506 is an abundant number, since it is smaller than the sum of its proper divisors (781408296).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

669778506 is a wasteful number, since it uses less digits than its factorization.

669778506 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 37209925 (or 37209922 counting only the distinct ones).

The product of its (nonzero) digits is 3810240, while the sum is 54.

The square root of 669778506 is about 25880.0793275446. The cubic root of 669778506 is about 874.9375763903.

It can be divided in two parts, 66977850 and 6, that added together give a square (66977856 = 8184²).

The spelling of 669778506 in words is "six hundred sixty-nine million, seven hundred seventy-eight thousand, five hundred six".