31666668 has 72 divisors (see below), whose sum is σ = 82359984. Its totient is φ = 9461760.

The previous prime is 31666643. The next prime is 31666693. The reversal of 31666668 is 86666613.

It is an interprime number because it is at equal distance from previous prime (31666643) and next prime (31666693).

It is an unprimeable number.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 163980 + ... + 164172.

Almost surely, 2^31666668 is an apocalyptic number.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 31666668, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (41179992).

31666668 is an abundant number, since it is smaller than the sum of its proper divisors (50693316).

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

31666668 is a wasteful number, since it uses less digits than its factorization.

31666668 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 335 (or 322 counting only the distinct ones).

The product of its digits is 186624, while the sum is 42.

The square root of 31666668 is about 5627.3144571812. The cubic root of 31666668 is about 316.3740030413.

Subtracting 31666668 from its reverse (86666613), we obtain a palindrome (54999945).

The spelling of 31666668 in words is "thirty-one million, six hundred sixty-six thousand, six hundred sixty-eight".