311391021 has 16 divisors (see below), whose sum is σ = 418880000. Its totient is φ = 205756848.

The previous prime is 311391013. The next prime is 311391053. The reversal of 311391021 is 120193113.

It is not a de Polignac number, because 311391021 - 2³ = 311391013 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (311391071) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 182430 + ... + 184128.

It is an arithmetic number, because the mean of its divisors is an integer number (26180000).

Almost surely, 2^311391021 is an apocalyptic number.

It is an amenable number.

311391021 is a deficient number, since it is larger than the sum of its proper divisors (107488979).

311391021 is a wasteful number, since it uses less digits than its factorization.

311391021 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2208.

The product of its (nonzero) digits is 162, while the sum is 21.

The square root of 311391021 is about 17646.2749893568. The cubic root of 311391021 is about 677.8007241467.

The spelling of 311391021 in words is "three hundred eleven million, three hundred ninety-one thousand, twenty-one".