31323021 has 16 divisors (see below), whose sum is σ = 42491904. Its totient is φ = 20521584.

The previous prime is 31322983. The next prime is 31323023. The reversal of 31323021 is 12032313.

It is not a de Polignac number, because 31323021 - 2⁶ = 31322957 is a prime.

It is a super-2 number, since 2×31323021² = 1962263289132882, which contains 22 as substring.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (31323023) 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 15 ways as a sum of consecutive naturals, for example, 51300 + ... + 51906.

It is an arithmetic number, because the mean of its divisors is an integer number (2655744).

Almost surely, 2^31323021 is an apocalyptic number.

It is an amenable number.

31323021 is a deficient number, since it is larger than the sum of its proper divisors (11168883).

31323021 is a wasteful number, since it uses less digits than its factorization.

31323021 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 880.

The product of its (nonzero) digits is 108, while the sum is 15.

The square root of 31323021 is about 5596.6973296758. The cubic root of 31323021 is about 315.2254068187.

Adding to 31323021 its reverse (12032313), we get a palindrome (43355334).

The spelling of 31323021 in words is "thirty-one million, three hundred twenty-three thousand, twenty-one".