31212221 has 8 divisors (see below), whose sum is σ = 33359040. Its totient is φ = 29099968.

The previous prime is 31212197. The next prime is 31212227. The reversal of 31212221 is 12221213.

It is a happy number.

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 31212221 - 2¹⁰ = 31211197 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 31212196 and 31212205.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (31212227) 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, 6761 + ... + 10398.

It is an arithmetic number, because the mean of its divisors is an integer number (4169880).

Almost surely, 2^31212221 is an apocalyptic number.

It is an amenable number.

31212221 is a deficient number, since it is larger than the sum of its proper divisors (2146819).

31212221 is a wasteful number, since it uses less digits than its factorization.

31212221 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 17283.

The product of its digits is 48, while the sum is 14.

The square root of 31212221 is about 5586.7898653878. The cubic root of 31212221 is about 314.8532818035.

Adding to 31212221 its reverse (12221213), we get a palindrome (43433434).

The spelling of 31212221 in words is "thirty-one million, two hundred twelve thousand, two hundred twenty-one".