31666398 has 16 divisors (see below), whose sum is σ = 63536400. Its totient is φ = 10521536.

The previous prime is 31666379. The next prime is 31666399. The reversal of 31666398 is 89366613.

It is a Smith number, since the sum of its digits (42) coincides with the sum of the digits of its prime factors. Since it is squarefree, it is also a hoax number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (31666399) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 6423 + ... + 10226.

It is an arithmetic number, because the mean of its divisors is an integer number (3971025).

Almost surely, 2^31666398 is an apocalyptic number.

31666398 is an abundant number, since it is smaller than the sum of its proper divisors (31870002).

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

31666398 is a wasteful number, since it uses less digits than its factorization.

31666398 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 16971.

The product of its digits is 139968, while the sum is 42.

The square root of 31666398 is about 5627.2904670010. The cubic root of 31666398 is about 316.3731038706.

The spelling of 31666398 in words is "thirty-one million, six hundred sixty-six thousand, three hundred ninety-eight".