668837731 has 4 divisors (see below), whose sum is σ = 668895192. Its totient is φ = 668780272.

The previous prime is 668837713. The next prime is 668837773. The reversal of 668837731 is 137738866.

It is a semiprime because it is the product of two primes, and also a brilliant number, because the two primes have the same length.

It is a cyclic number.

It is not a de Polignac number, because 668837731 - 2¹¹ = 668835683 is a prime.

It is a super-2 number, since 2×668837731² = 894687820818456722, which contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (668837711) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 4405 + ... + 36838.

It is an arithmetic number, because the mean of its divisors is an integer number (167223798).

Almost surely, 2^668837731 is an apocalyptic number.

668837731 is the 16357-th centered pentagonal number.

668837731 is a deficient number, since it is larger than the sum of its proper divisors (57461).

668837731 is a wasteful number, since it uses less digits than its factorization.

668837731 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 57460.

The product of its digits is 1016064, while the sum is 49.

The square root of 668837731 is about 25861.8972815221. The cubic root of 668837731 is about 874.5277368795.

The spelling of 668837731 in words is "six hundred sixty-eight million, eight hundred thirty-seven thousand, seven hundred thirty-one".