31445891 has 2 divisors, whose sum is σ = 31445892. Its totient is φ = 31445890.

The previous prime is 31445863. The next prime is 31445917. The reversal of 31445891 is 19854413.

It is a strong prime.

It is an emirp because it is prime and its reverse (19854413) is a distict prime.

It is a cyclic number.

It is not a de Polignac number, because 31445891 - 2¹⁴ = 31429507 is a prime.

It is not a weakly prime, because it can be changed into another prime (31445851) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 15722945 + 15722946.

It is an arithmetic number, because the mean of its divisors is an integer number (15722946).

Almost surely, 2^31445891 is an apocalyptic number.

31445891 is a deficient number, since it is larger than the sum of its proper divisors (1).

31445891 is an equidigital number, since it uses as much as digits as its factorization.

31445891 is an evil number, because the sum of its binary digits is even.

The product of its digits is 17280, while the sum is 35.

The square root of 31445891 is about 5607.6635954736. The cubic root of 31445891 is about 315.6370445490.

The spelling of 31445891 in words is "thirty-one million, four hundred forty-five thousand, eight hundred ninety-one".