331221013 has 4 divisors (see below), whose sum is σ = 350704620. Its totient is φ = 311737408.

The previous prime is 331220993. The next prime is 331221031. The reversal of 331221013 is 310122133.

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 142515844 + 188705169 = 11938^2 + 13737^2 .

It is a cyclic number.

It is not a de Polignac number, because 331221013 - 2¹³ = 331212821 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (331221043) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 9741778 + ... + 9741811.

It is an arithmetic number, because the mean of its divisors is an integer number (87676155).

Almost surely, 2^331221013 is an apocalyptic number.

It is an amenable number.

331221013 is a deficient number, since it is larger than the sum of its proper divisors (19483607).

331221013 is a wasteful number, since it uses less digits than its factorization.

331221013 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 19483606.

The product of its (nonzero) digits is 108, while the sum is 16.

The square root of 331221013 is about 18199.4783716457. The cubic root of 331221013 is about 691.8935685880.

Adding to 331221013 its reverse (310122133), we get a palindrome (641343146).

The spelling of 331221013 in words is "three hundred thirty-one million, two hundred twenty-one thousand, thirteen".