666998568 has 24 divisors (see below), whose sum is σ = 1806454650. Its totient is φ = 222332832.

The previous prime is 666998567. The next prime is 666998569. The reversal of 666998568 is 865899666.

It is an interprime number because it is at equal distance from previous prime (666998567) and next prime (666998569).

It can be written as a sum of positive squares in only one way, i.e., 501670404 + 165328164 = 22398^2 + 12858^2 .

It is a tau number, because it is divible by the number of its divisors (24).

It is not an unprimeable number, because it can be changed into a prime (666998561) 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, 4631863 + ... + 4632006.

Almost surely, 2^666998568 is an apocalyptic number.

It is an amenable number.

666998568 is an abundant number, since it is smaller than the sum of its proper divisors (1139456082).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

666998568 is a wasteful number, since it uses less digits than its factorization.

666998568 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 9263881 (or 9263874 counting only the distinct ones).

The product of its digits is 33592320, while the sum is 63.

The square root of 666998568 is about 25826.3154166443. The cubic root of 666998568 is about 873.7254119454.

The spelling of 666998568 in words is "six hundred sixty-six million, nine hundred ninety-eight thousand, five hundred sixty-eight".