31321091 has 4 divisors (see below), whose sum is σ = 31356384. Its totient is φ = 31285800.

The previous prime is 31321057. The next prime is 31321109. The reversal of 31321091 is 19012313.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 19012313 = 29 ⋅655597.

It is a cyclic number.

It is not a de Polignac number, because 31321091 - 2²² = 27126787 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (31321691) 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, 16280 + ... + 18101.

It is an arithmetic number, because the mean of its divisors is an integer number (7839096).

Almost surely, 2^31321091 is an apocalyptic number.

31321091 is a deficient number, since it is larger than the sum of its proper divisors (35293).

31321091 is an equidigital number, since it uses as much as digits as its factorization.

31321091 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 35292.

The product of its (nonzero) digits is 162, while the sum is 20.

The square root of 31321091 is about 5596.5249039024. The cubic root of 31321091 is about 315.2189323737.

The spelling of 31321091 in words is "thirty-one million, three hundred twenty-one thousand, ninety-one".