31201121 has 4 divisors (see below), whose sum is σ = 35658432. Its totient is φ = 26743812.

The previous prime is 31201109. The next prime is 31201139. The reversal of 31201121 is 12110213.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4, and also an emirpimes, since its reverse is a distinct semiprime: 12110213 = 23 ⋅526531.

It is a cyclic number.

It is not a de Polignac number, because 31201121 - 2¹⁴ = 31184737 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (31201321) 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 in 3 ways as a sum of consecutive naturals, for example, 2228645 + ... + 2228658.

It is an arithmetic number, because the mean of its divisors is an integer number (8914608).

Almost surely, 2^31201121 is an apocalyptic number.

It is an amenable number.

31201121 is a deficient number, since it is larger than the sum of its proper divisors (4457311).

31201121 is an equidigital number, since it uses as much as digits as its factorization.

31201121 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 4457310.

The product of its (nonzero) digits is 12, while the sum is 11.

The square root of 31201121 is about 5585.7963622030. The cubic root of 31201121 is about 314.8159536279.

Adding to 31201121 its reverse (12110213), we get a palindrome (43311334).

The spelling of 31201121 in words is "thirty-one million, two hundred one thousand, one hundred twenty-one".