155639 has 4 divisors (see below), whose sum is σ = 169800. Its totient is φ = 141480.

The previous prime is 155627. The next prime is 155653. The reversal of 155639 is 936551.

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 155639 - 2⁸ = 155383 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 (155609) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 7064 + ... + 7085.

It is an arithmetic number, because the mean of its divisors is an integer number (42450).

2¹⁵⁵⁶³⁹ is an apocalyptic number.

155639 is a deficient number, since it is larger than the sum of its proper divisors (14161).

155639 is a wasteful number, since it uses less digits than its factorization.

155639 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 14160.

The product of its digits is 4050, while the sum is 29.

The square root of 155639 is about 394.5110898315. The cubic root of 155639 is about 53.7905696954.

The spelling of 155639 in words is "one hundred fifty-five thousand, six hundred thirty-nine".