31204221 has 16 divisors (see below), whose sum is σ = 42364224. Its totient is φ = 20427264.

The previous prime is 31204211. The next prime is 31204237. The reversal of 31204221 is 12240213.

It is not a de Polignac number, because 31204221 - 2⁵ = 31204189 is a prime.

It is a Curzon number.

It is a self number, because there is not a number n which added to its sum of digits gives 31204221.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (31204211) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 45346 + ... + 46028.

It is an arithmetic number, because the mean of its divisors is an integer number (2647764).

Almost surely, 2^31204221 is an apocalyptic number.

It is an amenable number.

31204221 is a deficient number, since it is larger than the sum of its proper divisors (11160003).

31204221 is a wasteful number, since it uses less digits than its factorization.

31204221 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 940.

The product of its (nonzero) digits is 96, while the sum is 15.

The square root of 31204221 is about 5586.0738448395. The cubic root of 31204221 is about 314.8263795048.

Adding to 31204221 its reverse (12240213), we get a palindrome (43444434).

The spelling of 31204221 in words is "thirty-one million, two hundred four thousand, two hundred twenty-one".