31222221 has 8 divisors (see below), whose sum is σ = 41664480. Its totient is φ = 20797392.

The previous prime is 31222211. The next prime is 31222249. The reversal of 31222221 is 12222213.

It is a happy number.

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

It is not a de Polignac number, because 31222221 - 2⁶ = 31222157 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 31222221.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (31222211) 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, 646 + ... + 7928.

It is an arithmetic number, because the mean of its divisors is an integer number (5208060).

Almost surely, 2^31222221 is an apocalyptic number.

It is an amenable number.

31222221 is a deficient number, since it is larger than the sum of its proper divisors (10442259).

31222221 is a wasteful number, since it uses less digits than its factorization.

31222221 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 8715.

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

The square root of 31222221 is about 5587.6847620459. The cubic root of 31222221 is about 314.8869032134.

Adding to 31222221 its reverse (12222213), we get a palindrome (43444434).

It can be divided in two parts, 3 and 1222221, that multiplied together give a palindrome (3666663).

The spelling of 31222221 in words is "thirty-one million, two hundred twenty-two thousand, two hundred twenty-one".