331021221 has 24 divisors (see below), whose sum is σ = 464520000. Its totient is φ = 209654016.

The previous prime is 331021213. The next prime is 331021259. The reversal of 331021221 is 122120133.

It is not a de Polignac number, because 331021221 - 2³ = 331021213 is a prime.

It is a self number, because there is not a number n which added to its sum of digits gives 331021221.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (331021261) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 264405 + ... + 265653.

It is an arithmetic number, because the mean of its divisors is an integer number (19355000).

Almost surely, 2^331021221 is an apocalyptic number.

It is an amenable number.

331021221 is a deficient number, since it is larger than the sum of its proper divisors (133498779).

331021221 is a wasteful number, since it uses less digits than its factorization.

331021221 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1465 (or 1442 counting only the distinct ones).

The product of its (nonzero) digits is 72, while the sum is 15.

The square root of 331021221 is about 18193.9885951377. The cubic root of 331021221 is about 691.7544242322.

Adding to 331021221 its reverse (122120133), we get a palindrome (453141354).

It can be divided in two parts, 3310 and 21221, that added together give a triangular number (24531 = T₂₂₁).

The spelling of 331021221 in words is "three hundred thirty-one million, twenty-one thousand, two hundred twenty-one".