665616646 has 4 divisors (see below), whose sum is σ = 998424972. Its totient is φ = 332808322.

The previous prime is 665616547. The next prime is 665616647. The reversal of 665616646 is 646616566.

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

It is a junction number, because it is equal to n+sod(n) for n = 665616596 and 665616605.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (665616647) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 166404160 + ... + 166404163.

It is an arithmetic number, because the mean of its divisors is an integer number (249606243).

Almost surely, 2^665616646 is an apocalyptic number.

665616646 is a deficient number, since it is larger than the sum of its proper divisors (332808326).

665616646 is a wasteful number, since it uses less digits than its factorization.

665616646 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 332808325.

The product of its digits is 933120, while the sum is 46.

The square root of 665616646 is about 25799.5473991309. The cubic root of 665616646 is about 873.1215849643.

The spelling of 665616646 in words is "six hundred sixty-five million, six hundred sixteen thousand, six hundred forty-six".