155403 has 12 divisors (see below), whose sum is σ = 232128. Its totient is φ = 100080.

The previous prime is 155399. The next prime is 155413. The reversal of 155403 is 304551.

155403 is a nontrivial binomial coefficient, being equal to C(558, 2).

It is not a de Polignac number, because 155403 - 2² = 155399 is a prime.

155403 is a lucky number.

It is not an unprimeable number, because it can be changed into a prime (155413) by changing a digit.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 1 + ... + 557.

It is an arithmetic number, because the mean of its divisors is an integer number (19344).

2¹⁵⁵⁴⁰³ is an apocalyptic number.

155403 is the 557-th triangular number and also the 279-th hexagonal number.

155403 is a deficient number, since it is larger than the sum of its proper divisors (76725).

155403 is a wasteful number, since it uses less digits than its factorization.

155403 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 594 (or 591 counting only the distinct ones).

The product of its (nonzero) digits is 300, while the sum is 18.

The square root of 155403 is about 394.2118719673. The cubic root of 155403 is about 53.7633678667.

Adding to 155403 its reverse (304551), we get a palindrome (459954).

The spelling of 155403 in words is "one hundred fifty-five thousand, four hundred three".