31003121 has 4 divisors (see below), whose sum is σ = 32826852. Its totient is φ = 29179392.

The previous prime is 31003109. The next prime is 31003139. The reversal of 31003121 is 12130013.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 12130013 = 7 ⋅1732859.

It can be written as a sum of positive squares in 2 ways, for example, as 22800625 + 8202496 = 4775^2 + 2864^2 .

It is a cyclic number.

It is not a de Polignac number, because 31003121 - 2¹⁴ = 30986737 is a prime.

It is a super-2 number, since 2×31003121² = 1922387023481282, which contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (31003171) 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, 911840 + ... + 911873.

It is an arithmetic number, because the mean of its divisors is an integer number (8206713).

Almost surely, 2^31003121 is an apocalyptic number.

It is an amenable number.

31003121 is a deficient number, since it is larger than the sum of its proper divisors (1823731).

31003121 is a wasteful number, since it uses less digits than its factorization.

31003121 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1823730.

The product of its (nonzero) digits is 18, while the sum is 11.

The square root of 31003121 is about 5568.0446298499. The cubic root of 31003121 is about 314.1486070886.

Adding to 31003121 its reverse (12130013), we get a palindrome (43133134).

The spelling of 31003121 in words is "thirty-one million, three thousand, one hundred twenty-one".