331631221 has 4 divisors (see below), whose sum is σ = 331953292. Its totient is φ = 331309152.

The previous prime is 331631219. The next prime is 331631239. The reversal of 331631221 is 122136133.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 182547121 + 149084100 = 13511^2 + 12210^2 .

It is a cyclic number.

It is not a de Polignac number, because 331631221 - 2¹ = 331631219 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 331631192 and 331631201.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (331631281) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 159486 + ... + 161551.

It is an arithmetic number, because the mean of its divisors is an integer number (82988323).

Almost surely, 2^331631221 is an apocalyptic number.

It is an amenable number.

331631221 is a deficient number, since it is larger than the sum of its proper divisors (322071).

331631221 is a wasteful number, since it uses less digits than its factorization.

331631221 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 322070.

The product of its digits is 648, while the sum is 22.

The square root of 331631221 is about 18210.7446580309. The cubic root of 331631221 is about 692.1790810591.

Adding to 331631221 its reverse (122136133), we get a palindrome (453767354).

The spelling of 331631221 in words is "three hundred thirty-one million, six hundred thirty-one thousand, two hundred twenty-one".