331640521 has 3 divisors (see below), whose sum is σ = 331658733. Its totient is φ = 331622310.

The previous prime is 331640501. The next prime is 331640563. The reversal of 331640521 is 125046133.

The square root of 331640521 is 18211.

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

It is a semiprime because it is the product of two primes, and also a brilliant number, because the two primes have the same length.

It is not a de Polignac number, because 331640521 - 2⁵ = 331640489 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (331640501) by changing a digit.

It is a polite number, since it can be written in 2 ways as a sum of consecutive naturals, for example, 9106 + ... + 27316.

It is an arithmetic number, because the mean of its divisors is an integer number (110552911).

Almost surely, 2^331640521 is an apocalyptic number.

331640521 is the 18211-st square number.

331640521 is the 9106-th centered octagonal number.

It is an amenable number.

331640521 is a deficient number, since it is larger than the sum of its proper divisors (18212).

331640521 is an frugal number, since it uses more digits than its factorization.

331640521 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 36422 (or 18211 counting only the distinct ones).

The product of its (nonzero) digits is 2160, while the sum is 25.

The cubic root of 331640521 is about 692.1855513037.

Multiplying 331640521 by its sum of digits (25), we get a square (8291013025 = 91055²).

Adding to 331640521 its reverse (125046133), we get a palindrome (456686654).

The spelling of 331640521 in words is "three hundred thirty-one million, six hundred forty thousand, five hundred twenty-one".