31607221 has 12 divisors (see below), whose sum is σ = 33345900. Its totient is φ = 29955200.

The previous prime is 31607207. The next prime is 31607227. The reversal of 31607221 is 12270613.

It can be written as a sum of positive squares in 2 ways, for example, as 19704721 + 11902500 = 4439^2 + 3450^2 .

It is not a de Polignac number, because 31607221 - 2¹⁵ = 31574453 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 31607192 and 31607201.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (31607227) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 78621 + ... + 79021.

It is an arithmetic number, because the mean of its divisors is an integer number (2778825).

Almost surely, 2^31607221 is an apocalyptic number.

It is an amenable number.

31607221 is a deficient number, since it is larger than the sum of its proper divisors (1738679).

31607221 is a wasteful number, since it uses less digits than its factorization.

31607221 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 596 (or 573 counting only the distinct ones).

The product of its (nonzero) digits is 504, while the sum is 22.

The square root of 31607221 is about 5622.0299714605. The cubic root of 31607221 is about 316.1759055067.

Adding to 31607221 its reverse (12270613), we get a palindrome (43877834).

The spelling of 31607221 in words is "thirty-one million, six hundred seven thousand, two hundred twenty-one".