331720639 has 4 divisors (see below), whose sum is σ = 349179640. Its totient is φ = 314261640.

The previous prime is 331720633. The next prime is 331720673. The reversal of 331720639 is 936027133.

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

It is a cyclic number.

It is not a de Polignac number, because 331720639 - 2⁵ = 331720607 is a prime.

It is a super-2 number, since 2×331720639² = 220077164677136642, which contains 22 as substring.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (331720633) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 8729472 + ... + 8729509.

It is an arithmetic number, because the mean of its divisors is an integer number (87294910).

Almost surely, 2^331720639 is an apocalyptic number.

331720639 is a deficient number, since it is larger than the sum of its proper divisors (17459001).

331720639 is a wasteful number, since it uses less digits than its factorization.

331720639 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 17459000.

The product of its (nonzero) digits is 20412, while the sum is 34.

The square root of 331720639 is about 18213.1995816221. The cubic root of 331720639 is about 692.2412864077.

The spelling of 331720639 in words is "three hundred thirty-one million, seven hundred twenty thousand, six hundred thirty-nine".