665620637 has 12 divisors (see below), whose sum is σ = 732603900. Its totient is φ = 604306560.

The previous prime is 665620633. The next prime is 665620649. The reversal of 665620637 is 736026566.

665620637 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It can be written as a sum of positive squares in 2 ways, for example, as 355473316 + 310147321 = 18854^2 + 17611^2 .

It is not a de Polignac number, because 665620637 - 2² = 665620633 is a prime.

It is a super-4 number, since 4×665620637⁴ (a number of 36 digits) contains 4444 as substring.

It is a hoax number, since the sum of its digits (41) coincides with the sum of the digits of its distinct prime factors.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 665620594 and 665620603.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (665620633) by changing a digit.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 99989 + ... + 106437.

It is an arithmetic number, because the mean of its divisors is an integer number (61050325).

Almost surely, 2^665620637 is an apocalyptic number.

It is an amenable number.

665620637 is a deficient number, since it is larger than the sum of its proper divisors (66983263).

665620637 is a wasteful number, since it uses less digits than its factorization.

665620637 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 7324 (or 7313 counting only the distinct ones).

The product of its (nonzero) digits is 272160, while the sum is 41.

The square root of 665620637 is about 25799.6247453330. The cubic root of 665620637 is about 873.1233300235.

The spelling of 665620637 in words is "six hundred sixty-five million, six hundred twenty thousand, six hundred thirty-seven".