669906810 has 48 divisors (see below), whose sum is σ = 1748022120. Its totient is φ = 177999360.

The previous prime is 669906799. The next prime is 669906817. The reversal of 669906810 is 18609966.

It can be written as a sum of positive squares in 4 ways, for example, as 506655081 + 163251729 = 22509^2 + 12777^2 .

It is a super-2 number, since 2×669906810² = 897550268168752200, which contains 22 as substring.

It is a Harshad number since it is a multiple of its sum of digits (45).

It is not an unprimeable number, because it can be changed into a prime (669906817) by changing a digit.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 12046 + ... + 38534.

Almost surely, 2^669906810 is an apocalyptic number.

669906810 is an abundant number, since it is smaller than the sum of its proper divisors (1078115310).

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

669906810 is a wasteful number, since it uses less digits than its factorization.

669906810 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 26783 (or 26780 counting only the distinct ones).

The product of its (nonzero) digits is 139968, while the sum is 45.

The square root of 669906810 is about 25882.5580265939. The cubic root of 669906810 is about 874.9934410393.

The spelling of 669906810 in words is "six hundred sixty-nine million, nine hundred six thousand, eight hundred ten".