331021636 has 27 divisors (see below), whose sum is σ = 637508767. Its totient is φ = 150282440.

The previous prime is 331021633. The next prime is 331021643. The reversal of 331021636 is 636120133.

The square root of 331021636 is 18194.

It is a perfect power (a square), and thus also a powerful number.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 331021636.

It is not an unprimeable number, because it can be changed into a prime (331021633) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 8 ways as a sum of consecutive naturals, for example, 399855 + ... + 400681.

Almost surely, 2^331021636 is an apocalyptic number.

331021636 is the 18194-th square number.

It is an amenable number.

331021636 is a deficient number, since it is larger than the sum of its proper divisors (306487131).

331021636 is an equidigital number, since it uses as much as digits as its factorization.

331021636 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1680 (or 840 counting only the distinct ones).

The product of its (nonzero) digits is 1944, while the sum is 25.

The cubic root of 331021636 is about 691.7547133153.

Multiplying 331021636 by its sum of digits (25), we get a square (8275540900 = 90970²).

Adding to 331021636 its reverse (636120133), we get a palindrome (967141769).

The spelling of 331021636 in words is "three hundred thirty-one million, twenty-one thousand, six hundred thirty-six".