665355690 has 48 divisors (see below), whose sum is σ = 1831689288. Its totient is φ = 166990848.

The previous prime is 665355637. The next prime is 665355701. The reversal of 665355690 is 96553566.

665355690 is a `hidden beast` number, since 6 + 6 + 5 + 3 + 556 + 90 = 666.

It can be written as a sum of positive squares in 4 ways, for example, as 662702049 + 2653641 = 25743^2 + 1629^2 .

It is a super-2 number, since 2×665355690² = 885396388430752200, which contains 22 as substring.

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

It is an unprimeable number.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 215907 + ... + 218966.

Almost surely, 2^665355690 is an apocalyptic number.

665355690 is an abundant number, since it is smaller than the sum of its proper divisors (1166333598).

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

665355690 is a wasteful number, since it uses less digits than its factorization.

665355690 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 434903 (or 434900 counting only the distinct ones).

The product of its (nonzero) digits is 729000, while the sum is 45.

The square root of 665355690 is about 25794.4895278042. The cubic root of 665355690 is about 873.0074671759.

The spelling of 665355690 in words is "six hundred sixty-five million, three hundred fifty-five thousand, six hundred ninety".