31023121 has 4 divisors (see below), whose sum is σ = 31041252. Its totient is φ = 31004992.

The previous prime is 31023107. The next prime is 31023137. The reversal of 31023121 is 12132013.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 12132013 = 19 ⋅638527.

It can be written as a sum of positive squares in 2 ways, for example, as 26010000 + 5013121 = 5100^2 + 2239^2 .

It is a cyclic number.

It is not a de Polignac number, because 31023121 - 2¹⁵ = 30990353 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (31023191) 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, 6196 + ... + 10021.

It is an arithmetic number, because the mean of its divisors is an integer number (7760313).

Almost surely, 2^31023121 is an apocalyptic number.

It is an amenable number.

31023121 is a deficient number, since it is larger than the sum of its proper divisors (18131).

31023121 is a wasteful number, since it uses less digits than its factorization.

31023121 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 18130.

The product of its (nonzero) digits is 36, while the sum is 13.

The square root of 31023121 is about 5569.8403029171. The cubic root of 31023121 is about 314.2161446072.

Adding to 31023121 its reverse (12132013), we get a palindrome (43155134).

The spelling of 31023121 in words is "thirty-one million, twenty-three thousand, one hundred twenty-one".