31625221 has 8 divisors (see below), whose sum is σ = 32052888. Its totient is φ = 31200000.

The previous prime is 31625179. The next prime is 31625261. The reversal of 31625221 is 12252613.

It can be written as a sum of positive squares in 4 ways, for example, as 15100996 + 16524225 = 3886^2 + 4065^2 .

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

It is a cyclic number.

It is not a de Polignac number, because 31625221 - 2¹¹ = 31623173 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 31625192 and 31625201.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (31625261) 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, 52321 + ... + 52921.

It is an arithmetic number, because the mean of its divisors is an integer number (4006611).

Almost surely, 2^31625221 is an apocalyptic number.

It is an amenable number.

31625221 is a deficient number, since it is larger than the sum of its proper divisors (427667).

31625221 is a wasteful number, since it uses less digits than its factorization.

31625221 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1223.

The product of its digits is 720, while the sum is 22.

The square root of 31625221 is about 5623.6305888634. The cubic root of 31625221 is about 316.2359138013.

Adding to 31625221 its reverse (12252613), we get a palindrome (43877834).

The spelling of 31625221 in words is "thirty-one million, six hundred twenty-five thousand, two hundred twenty-one".