665531956 has 24 divisors (see below), whose sum is σ = 1218276864. Its totient is φ = 317523360.

The previous prime is 665531953. The next prime is 665531957. The reversal of 665531956 is 659135566.

It is a Harshad number since it is a multiple of its sum of digits (46).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (665531953) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 30141 + ... + 47323.

It is an arithmetic number, because the mean of its divisors is an integer number (50761536).

Almost surely, 2^665531956 is an apocalyptic number.

It is an amenable number.

665531956 is a deficient number, since it is larger than the sum of its proper divisors (552744908).

665531956 is a wasteful number, since it uses less digits than its factorization.

665531956 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 17631 (or 17629 counting only the distinct ones).

The product of its digits is 729000, while the sum is 46.

The square root of 665531956 is about 25797.9060390567. The cubic root of 665531956 is about 873.0845527357.

The spelling of 665531956 in words is "six hundred sixty-five million, five hundred thirty-one thousand, nine hundred fifty-six".