165542399 has 6 divisors (see below), whose sum is σ = 181959960. Its totient is φ = 150492980.

The previous prime is 165542381. The next prime is 165542407. The reversal of 165542399 is 993245561.

It is not a de Polignac number, because 165542399 - 2¹⁶ = 165476863 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (165542099) 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, 683939 + ... + 684180.

It is an arithmetic number, because the mean of its divisors is an integer number (30326660).

Almost surely, 2^165542399 is an apocalyptic number.

165542399 is a deficient number, since it is larger than the sum of its proper divisors (16417561).

165542399 is a wasteful number, since it uses less digits than its factorization.

165542399 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1368141 (or 1368130 counting only the distinct ones).

The product of its digits is 291600, while the sum is 44.

The square root of 165542399 is about 12866.3281086719. The cubic root of 165542399 is about 549.0809986185.

The spelling of 165542399 in words is "one hundred sixty-five million, five hundred forty-two thousand, three hundred ninety-nine".