668133961 has 4 divisors (see below), whose sum is σ = 728873424. Its totient is φ = 607394500.

The previous prime is 668133931. The next prime is 668133967. The reversal of 668133961 is 169331866.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is a cyclic number.

It is not a de Polignac number, because 668133961 - 2¹³ = 668125769 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (668133967) 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, 30369715 + ... + 30369736.

It is an arithmetic number, because the mean of its divisors is an integer number (182218356).

Almost surely, 2^668133961 is an apocalyptic number.

It is an amenable number.

668133961 is a deficient number, since it is larger than the sum of its proper divisors (60739463).

668133961 is a wasteful number, since it uses less digits than its factorization.

668133961 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 60739462.

The product of its digits is 139968, while the sum is 43.

The square root of 668133961 is about 25848.2873900767. The cubic root of 668133961 is about 874.2208949488.

The spelling of 668133961 in words is "six hundred sixty-eight million, one hundred thirty-three thousand, nine hundred sixty-one".