669999945 has 16 divisors (see below), whose sum is σ = 1128421440. Its totient is φ = 338526144.

The previous prime is 669999887. The next prime is 669999947. The reversal of 669999945 is 549999966.

It is not a de Polignac number, because 669999945 - 2⁶ = 669999881 is a prime.

It is not an unprimeable number, because it can be changed into a prime (669999947) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 1175154 + ... + 1175723.

It is an arithmetic number, because the mean of its divisors is an integer number (70526340).

Almost surely, 2^669999945 is an apocalyptic number.

It is an amenable number.

669999945 is a deficient number, since it is larger than the sum of its proper divisors (458421495).

669999945 is a wasteful number, since it uses less digits than its factorization.

669999945 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2350904.

The product of its digits is 42515280, while the sum is 66.

The square root of 669999945 is about 25884.3571486719. The cubic root of 669999945 is about 875.0339883396.

The spelling of 669999945 in words is "six hundred sixty-nine million, nine hundred ninety-nine thousand, nine hundred forty-five".