665621236 has 24 divisors (see below), whose sum is σ = 1338011136. Its totient is φ = 283815840.

The previous prime is 665621221. The next prime is 665621249. The reversal of 665621236 is 632126566.

It is a junction number, because it is equal to n+sod(n) for n = 665621195 and 665621204.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 54820 + ... + 65851.

It is an arithmetic number, because the mean of its divisors is an integer number (55750464).

Almost surely, 2^665621236 is an apocalyptic number.

It is an amenable number.

665621236 is an abundant number, since it is smaller than the sum of its proper divisors (672389900).

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

665621236 is a wasteful number, since it uses less digits than its factorization.

665621236 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 120879 (or 120877 counting only the distinct ones).

The product of its digits is 77760, while the sum is 37.

The square root of 665621236 is about 25799.6363540264. The cubic root of 665621236 is about 873.1235919348.

The spelling of 665621236 in words is "six hundred sixty-five million, six hundred twenty-one thousand, two hundred thirty-six".