31121387 has 4 divisors (see below), whose sum is σ = 33950616. Its totient is φ = 28292160.

The previous prime is 31121381. The next prime is 31121393. The reversal of 31121387 is 78312113.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 78312113 = 11 ⋅7119283.

It is an interprime number because it is at equal distance from previous prime (31121381) and next prime (31121393).

It is a cyclic number.

It is not a de Polignac number, because 31121387 - 2⁴ = 31121371 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (31121381) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 1414598 + ... + 1414619.

It is an arithmetic number, because the mean of its divisors is an integer number (8487654).

Almost surely, 2^31121387 is an apocalyptic number.

31121387 is a deficient number, since it is larger than the sum of its proper divisors (2829229).

31121387 is a wasteful number, since it uses less digits than its factorization.

31121387 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2829228.

The product of its digits is 1008, while the sum is 26.

The square root of 31121387 is about 5578.6545869053. The cubic root of 31121387 is about 314.5475557088.

The spelling of 31121387 in words is "thirty-one million, one hundred twenty-one thousand, three hundred eighty-seven".