31866161 has 4 divisors (see below), whose sum is σ = 31878000. Its totient is φ = 31854324.

The previous prime is 31866127. The next prime is 31866169. The reversal of 31866161 is 16166813.

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, 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 31866161 - 2¹⁴ = 31849777 is a prime.

It is a Duffinian number.

It is a Curzon number.

It is not an unprimeable number, because it can be changed into a prime (31866169) 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, 290 + ... + 7988.

It is an arithmetic number, because the mean of its divisors is an integer number (7969500).

Almost surely, 2^31866161 is an apocalyptic number.

It is an amenable number.

31866161 is a deficient number, since it is larger than the sum of its proper divisors (11839).

31866161 is an equidigital number, since it uses as much as digits as its factorization.

31866161 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 11838.

The product of its digits is 5184, while the sum is 32.

The square root of 31866161 is about 5645.0120460456. The cubic root of 31866161 is about 317.0369748589.

The spelling of 31866161 in words is "thirty-one million, eight hundred sixty-six thousand, one hundred sixty-one".