31623121 has 2 divisors, whose sum is σ = 31623122. Its totient is φ = 31623120.

The previous prime is 31623113. The next prime is 31623167. The reversal of 31623121 is 12132613.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 30747025 + 876096 = 5545^2 + 936^2 .

It is an emirp because it is prime and its reverse (12132613) is a distict prime.

It is a cyclic number.

It is not a de Polignac number, because 31623121 - 2³ = 31623113 is a prime.

It is not a weakly prime, because it can be changed into another prime (31623181) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 15811560 + 15811561.

It is an arithmetic number, because the mean of its divisors is an integer number (15811561).

Almost surely, 2^31623121 is an apocalyptic number.

It is an amenable number.

31623121 is a deficient number, since it is larger than the sum of its proper divisors (1).

31623121 is an equidigital number, since it uses as much as digits as its factorization.

31623121 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 216, while the sum is 19.

The square root of 31623121 is about 5623.4438736418. The cubic root of 31623121 is about 316.2289140071.

Adding to 31623121 its reverse (12132613), we get a palindrome (43755734).

The spelling of 31623121 in words is "thirty-one million, six hundred twenty-three thousand, one hundred twenty-one".