31221425 has 6 divisors (see below), whose sum is σ = 38714598. Its totient is φ = 24977120.

The previous prime is 31221413. The next prime is 31221431. The reversal of 31221425 is 52412213.

It can be written as a sum of positive squares in 3 ways, for example, as 2050624 + 29170801 = 1432^2 + 5401^2 .

It is not a de Polignac number, because 31221425 - 2¹⁸ = 30959281 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 31221397 and 31221406.

It is an unprimeable number.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 624404 + ... + 624453.

It is an arithmetic number, because the mean of its divisors is an integer number (6452433).

Almost surely, 2^31221425 is an apocalyptic number.

It is an amenable number.

31221425 is a deficient number, since it is larger than the sum of its proper divisors (7493173).

31221425 is a wasteful number, since it uses less digits than its factorization.

31221425 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1248867 (or 1248862 counting only the distinct ones).

The product of its digits is 480, while the sum is 20.

The square root of 31221425 is about 5587.6135335222. The cubic root of 31221425 is about 314.8842272122.

Adding to 31221425 its reverse (52412213), we get a palindrome (83633638).

The spelling of 31221425 in words is "thirty-one million, two hundred twenty-one thousand, four hundred twenty-five".