668617947 has 6 divisors (see below), whose sum is σ = 965781492. Its totient is φ = 445745292.

The previous prime is 668617933. The next prime is 668617987. The reversal of 668617947 is 749716866.

It is a happy number.

It is not a de Polignac number, because 668617947 - 2⁴ = 668617931 is a prime.

It is a junction number, because it is equal to n+sod(n) for n = 668617893 and 668617902.

It is not an unprimeable number, because it can be changed into a prime (668617907) by changing a digit.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 37145433 + ... + 37145450.

It is an arithmetic number, because the mean of its divisors is an integer number (160963582).

Almost surely, 2^668617947 is an apocalyptic number.

668617947 is a deficient number, since it is larger than the sum of its proper divisors (297163545).

668617947 is a wasteful number, since it uses less digits than its factorization.

668617947 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 74290889 (or 74290886 counting only the distinct ones).

The product of its digits is 3048192, while the sum is 54.

The square root of 668617947 is about 25857.6477468466. The cubic root of 668617947 is about 874.4319347377.

The spelling of 668617947 in words is "six hundred sixty-eight million, six hundred seventeen thousand, nine hundred forty-seven".