165605639 has 2 divisors, whose sum is σ = 165605640. Its totient is φ = 165605638.

The previous prime is 165605633. The next prime is 165605663. The reversal of 165605639 is 936506561.

It is a weak prime.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-165605639 is a prime.

It is a Chen prime.

It is a junction number, because it is equal to n+sod(n) for n = 165605596 and 165605605.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (165605633) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 82802819 + 82802820.

It is an arithmetic number, because the mean of its divisors is an integer number (82802820).

Almost surely, 2^165605639 is an apocalyptic number.

165605639 is a deficient number, since it is larger than the sum of its proper divisors (1).

165605639 is an equidigital number, since it uses as much as digits as its factorization.

165605639 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 145800, while the sum is 41.

The square root of 165605639 is about 12868.7854516267. The cubic root of 165605639 is about 549.1509091305.

The spelling of 165605639 in words is "one hundred sixty-five million, six hundred five thousand, six hundred thirty-nine".