31000121 has 4 divisors (see below), whose sum is σ = 31197732. Its totient is φ = 30802512.

The previous prime is 31000087. The next prime is 31000127. The reversal of 31000121 is 12100013.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 12100013 = 31 ⋅390323.

It can be written as a sum of positive squares in 2 ways, for example, as 8065600 + 22934521 = 2840^2 + 4789^2 .

It is a cyclic number.

It is not a de Polignac number, because 31000121 - 2¹⁸ = 30737977 is a prime.

It is a super-2 number, since 2×31000121² = 1922015004029282, which contains 22 as substring.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 31000099 and 31000108.

It is not an unprimeable number, because it can be changed into a prime (31000127) 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, 98570 + ... + 98883.

It is an arithmetic number, because the mean of its divisors is an integer number (7799433).

Almost surely, 2^31000121 is an apocalyptic number.

It is an amenable number.

31000121 is a deficient number, since it is larger than the sum of its proper divisors (197611).

31000121 is a wasteful number, since it uses less digits than its factorization.

31000121 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 197610.

The product of its (nonzero) digits is 6, while the sum is 8.

The square root of 31000121 is about 5567.7752289402. The cubic root of 31000121 is about 314.1384739559.

Adding to 31000121 its reverse (12100013), we get a palindrome (43100134).

It can be divided in two parts, 3100012 and 1, that added together give a palindrome (3100013).

The spelling of 31000121 in words is "thirty-one million, one hundred twenty-one", and thus it is an aban number.