165720399 has 8 divisors (see below), whose sum is σ = 237957552. Its totient is φ = 101981760.

The previous prime is 165720397. The next prime is 165720407. The reversal of 165720399 is 993027561.

165720399 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a sphenic number, since it is the product of 3 distinct primes.

It is not a de Polignac number, because 165720399 - 2¹ = 165720397 is a prime.

It is a self number, because there is not a number n which added to its sum of digits gives 165720399.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (165720397) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 2124582 + ... + 2124659.

It is an arithmetic number, because the mean of its divisors is an integer number (29744694).

Almost surely, 2^165720399 is an apocalyptic number.

165720399 is a deficient number, since it is larger than the sum of its proper divisors (72237153).

165720399 is a wasteful number, since it uses less digits than its factorization.

165720399 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 4249257.

The product of its (nonzero) digits is 102060, while the sum is 42.

The square root of 165720399 is about 12873.2435306724. The cubic root of 165720399 is about 549.2777284972.

The spelling of 165720399 in words is "one hundred sixty-five million, seven hundred twenty thousand, three hundred ninety-nine".