668531401 has 4 divisors (see below), whose sum is σ = 669187204. Its totient is φ = 667875600.

The previous prime is 668531393. The next prime is 668531411. The reversal of 668531401 is 104135866.

It is a happy number.

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

It can be written as a sum of positive squares in 2 ways, for example, as 288320400 + 380211001 = 16980^2 + 19499^2 .

It is a cyclic number.

It is not a de Polignac number, because 668531401 - 2³ = 668531393 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (668531411) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 326370 + ... + 328411.

It is an arithmetic number, because the mean of its divisors is an integer number (167296801).

Almost surely, 2^668531401 is an apocalyptic number.

It is an amenable number.

668531401 is a deficient number, since it is larger than the sum of its proper divisors (655803).

668531401 is a wasteful number, since it uses less digits than its factorization.

668531401 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 655802.

The product of its (nonzero) digits is 17280, while the sum is 34.

The square root of 668531401 is about 25855.9741839289. The cubic root of 668531401 is about 874.3942042460.

The spelling of 668531401 in words is "six hundred sixty-eight million, five hundred thirty-one thousand, four hundred one".