31430891 has 4 divisors (see below), whose sum is σ = 31442112. Its totient is φ = 31419672.

The previous prime is 31430879. The next prime is 31430899. The reversal of 31430891 is 19803413.

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 31430891 - 2¹⁴ = 31414507 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (31430899) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 2501 + ... + 8313.

It is an arithmetic number, because the mean of its divisors is an integer number (7860528).

Almost surely, 2^31430891 is an apocalyptic number.

31430891 is a deficient number, since it is larger than the sum of its proper divisors (11221).

31430891 is an equidigital number, since it uses as much as digits as its factorization.

31430891 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 11220.

The product of its (nonzero) digits is 2592, while the sum is 29.

The square root of 31430891 is about 5606.3259805331. The cubic root of 31430891 is about 315.5868492397.

The spelling of 31430891 in words is "thirty-one million, four hundred thirty thousand, eight hundred ninety-one".