331388609 has 6 divisors (see below), whose sum is σ = 339590706. Its totient is φ = 323192240.

The previous prime is 331388591. The next prime is 331388611. The reversal of 331388609 is 906883133.

It can be written as a sum of positive squares in only one way, i.e., 202066225 + 129322384 = 14215^2 + 11372^2 .

It is not a de Polignac number, because 331388609 - 2⁸ = 331388353 is a prime.

It is a Harshad number since it is a multiple of its sum of digits (41).

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (331388689) by changing a digit.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 115142 + ... + 117984.

It is an arithmetic number, because the mean of its divisors is an integer number (56598451).

Almost surely, 2^331388609 is an apocalyptic number.

It is an amenable number.

331388609 is a deficient number, since it is larger than the sum of its proper divisors (8202097).

331388609 is an frugal number, since it uses more digits than its factorization.

331388609 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 5727 (or 2884 counting only the distinct ones).

The product of its (nonzero) digits is 93312, while the sum is 41.

The square root of 331388609 is about 18204.0822070216. The cubic root of 331388609 is about 692.0102470166.

Multiplying 331388609 by its sum of digits (41), we get a square (13586932969 = 116563²).

331388609 divided by its sum of digits (41) gives a square (8082649 = 2843²).

The spelling of 331388609 in words is "three hundred thirty-one million, three hundred eighty-eight thousand, six hundred nine".