155729 has 4 divisors (see below), whose sum is σ = 177984. Its totient is φ = 133476.

The previous prime is 155723. The next prime is 155731. The reversal of 155729 is 927551.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4, and also an emirpimes, since its reverse is a distinct semiprime: 927551 = 31 ⋅29921.

It is not a de Polignac number, because 155729 - 2⁸ = 155473 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (155723) 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, 11117 + ... + 11130.

It is an arithmetic number, because the mean of its divisors is an integer number (44496).

2¹⁵⁵⁷²⁹ is an apocalyptic number.

It is an amenable number.

155729 is a deficient number, since it is larger than the sum of its proper divisors (22255).

155729 is an equidigital number, since it uses as much as digits as its factorization.

155729 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 22254.

The product of its digits is 3150, while the sum is 29.

The square root of 155729 is about 394.6251385809. The cubic root of 155729 is about 53.8009360312.

The spelling of 155729 in words is "one hundred fifty-five thousand, seven hundred twenty-nine".