669804961 has 6 divisors (see below), whose sum is σ = 779160930. Its totient is φ = 574118496.

The previous prime is 669804953. The next prime is 669804973. The reversal of 669804961 is 169408966.

It can be written as a sum of positive squares in only one way, i.e., 509630625 + 160174336 = 22575^2 + 12656^2 .

It is not a de Polignac number, because 669804961 - 2³ = 669804953 is a prime.

It is a Harshad number since it is a multiple of its sum of digits (49), and also a Moran number because the ratio is a prime number: 13669489 = 669804961 / (6 + 6 + 9 + 8 + 0 + 4 + 9 + 6 + 1).

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (669804931) by changing a digit.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 6834696 + ... + 6834793.

It is an arithmetic number, because the mean of its divisors is an integer number (129860155).

Almost surely, 2^669804961 is an apocalyptic number.

It is an amenable number.

669804961 is a deficient number, since it is larger than the sum of its proper divisors (109355969).

669804961 is a wasteful number, since it uses less digits than its factorization.

669804961 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 13669503 (or 13669496 counting only the distinct ones).

The product of its (nonzero) digits is 559872, while the sum is 49.

The square root of 669804961 is about 25880.5904298955. The cubic root of 669804961 is about 874.9490957053.

The spelling of 669804961 in words is "six hundred sixty-nine million, eight hundred four thousand, nine hundred sixty-one".