31121421 has 8 divisors (see below), whose sum is σ = 41549760. Its totient is φ = 20720352.

The previous prime is 31121413. The next prime is 31121479. The reversal of 31121421 is 12412113.

It is a sphenic number, since it is the product of 3 distinct primes.

It is not a de Polignac number, because 31121421 - 2³ = 31121413 is a prime.

It is a self number, because there is not a number n which added to its sum of digits gives 31121421.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (31121401) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 3985 + ... + 8838.

It is an arithmetic number, because the mean of its divisors is an integer number (5193720).

Almost surely, 2^31121421 is an apocalyptic number.

It is an amenable number.

31121421 is a deficient number, since it is larger than the sum of its proper divisors (10428339).

31121421 is a wasteful number, since it uses less digits than its factorization.

31121421 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 13635.

The product of its digits is 48, while the sum is 15.

The square root of 31121421 is about 5578.6576342342. The cubic root of 31121421 is about 314.5476702561.

Adding to 31121421 its reverse (12412113), we get a palindrome (43533534).

The spelling of 31121421 in words is "thirty-one million, one hundred twenty-one thousand, four hundred twenty-one".