155155321 has 4 divisors (see below), whose sum is σ = 155542644. Its totient is φ = 154768000.

The previous prime is 155155313. The next prime is 155155409. The reversal of 155155321 is 123551551.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 134096400 + 21058921 = 11580^2 + 4589^2 .

It is a cyclic number.

It is not a de Polignac number, because 155155321 - 2³ = 155155313 is a prime.

It is a super-2 number, since 2×155155321² = 48146347269226082, which contains 22 as substring.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 155155321.

It is not an unprimeable number, because it can be changed into a prime (155155421) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 193060 + ... + 193861.

It is an arithmetic number, because the mean of its divisors is an integer number (38885661).

Almost surely, 2^155155321 is an apocalyptic number.

It is an amenable number.

155155321 is a deficient number, since it is larger than the sum of its proper divisors (387323).

155155321 is an equidigital number, since it uses as much as digits as its factorization.

155155321 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 387322.

The product of its digits is 3750, while the sum is 28.

The square root of 155155321 is about 12456.1358775505. The cubic root of 155155321 is about 537.3479025930.

The spelling of 155155321 in words is "one hundred fifty-five million, one hundred fifty-five thousand, three hundred twenty-one".