665646635 has 4 divisors (see below), whose sum is σ = 798775968. Its totient is φ = 532517304.

The previous prime is 665646593. The next prime is 665646643. The reversal of 665646635 is 536646566.

It is a semiprime because it is the product of two primes.

It is a cyclic number.

It is not a de Polignac number, because 665646635 - 2¹⁶ = 665581099 is a prime.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 665646635.

It is an unprimeable number.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 66564659 + ... + 66564668.

It is an arithmetic number, because the mean of its divisors is an integer number (199693992).

Almost surely, 2^665646635 is an apocalyptic number.

665646635 is a deficient number, since it is larger than the sum of its proper divisors (133129333).

665646635 is a wasteful number, since it uses less digits than its factorization.

665646635 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 133129332.

The product of its digits is 2332800, while the sum is 47.

The square root of 665646635 is about 25800.1285849509. The cubic root of 665646635 is about 873.1346974419.

The spelling of 665646635 in words is "six hundred sixty-five million, six hundred forty-six thousand, six hundred thirty-five".