31213421 has 4 divisors (see below), whose sum is σ = 31335132. Its totient is φ = 31091712.

The previous prime is 31213417. The next prime is 31213433. The reversal of 31213421 is 12431213.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 12431213 = 2467 ⋅5039.

It can be written as a sum of positive squares in 2 ways, for example, as 29214025 + 1999396 = 5405^2 + 1414^2 .

It is a cyclic number.

It is not a de Polignac number, because 31213421 - 2² = 31213417 is a prime.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 31213421.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (31213321) 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, 60470 + ... + 60983.

It is an arithmetic number, because the mean of its divisors is an integer number (7833783).

Almost surely, 2^31213421 is an apocalyptic number.

It is an amenable number.

31213421 is a deficient number, since it is larger than the sum of its proper divisors (121711).

31213421 is a wasteful number, since it uses less digits than its factorization.

31213421 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 121710.

The product of its digits is 144, while the sum is 17.

The square root of 31213421 is about 5586.8972605553. The cubic root of 31213421 is about 314.8573167519.

Adding to 31213421 its reverse (12431213), we get a palindrome (43644634).

The spelling of 31213421 in words is "thirty-one million, two hundred thirteen thousand, four hundred twenty-one".