668615249 has 16 divisors (see below), whose sum is σ = 700170240. Its totient is φ = 637943040.

The previous prime is 668615243. The next prime is 668615257. The reversal of 668615249 is 942516866.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-668615249 is a prime.

It is a Smith number, since the sum of its digits (47) coincides with the sum of the digits of its prime factors. Since it is squarefree, it is also a hoax number.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (668615243) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 379232 + ... + 380990.

It is an arithmetic number, because the mean of its divisors is an integer number (43760640).

Almost surely, 2^668615249 is an apocalyptic number.

It is an amenable number.

668615249 is a deficient number, since it is larger than the sum of its proper divisors (31554991).

668615249 is a wasteful number, since it uses less digits than its factorization.

668615249 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2000.

The product of its digits is 622080, while the sum is 47.

The square root of 668615249 is about 25857.5955765419. The cubic root of 668615249 is about 874.4307585700.

The spelling of 668615249 in words is "six hundred sixty-eight million, six hundred fifteen thousand, two hundred forty-nine".