31213189 has 4 divisors (see below), whose sum is σ = 35672224. Its totient is φ = 26754156.

The previous prime is 31213159. The next prime is 31213201. The reversal of 31213189 is 98131213.

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 an emirpimes, since its reverse is a distinct semiprime: 98131213 = 31 ⋅3165523.

It is a cyclic number.

It is not a de Polignac number, because 31213189 - 2⁵ = 31213157 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (31213109) 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, 2229507 + ... + 2229520.

It is an arithmetic number, because the mean of its divisors is an integer number (8918056).

Almost surely, 2^31213189 is an apocalyptic number.

It is an amenable number.

31213189 is a deficient number, since it is larger than the sum of its proper divisors (4459035).

31213189 is an equidigital number, since it uses as much as digits as its factorization.

31213189 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 4459034.

The product of its digits is 1296, while the sum is 28.

The square root of 31213189 is about 5586.8764976505. The cubic root of 31213189 is about 314.8565366699.

The spelling of 31213189 in words is "thirty-one million, two hundred thirteen thousand, one hundred eighty-nine".