155155221 has 48 divisors (see below), whose sum is σ = 249080832. Its totient is φ = 92476800.

The previous prime is 155155211. The next prime is 155155229. The reversal of 155155221 is 122551551.

It is not a de Polignac number, because 155155221 - 2⁹ = 155154709 is a prime.

It is a Curzon number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (155155229) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 47 ways as a sum of consecutive naturals, for example, 812236 + ... + 812426.

It is an arithmetic number, because the mean of its divisors is an integer number (5189184).

Almost surely, 2^155155221 is an apocalyptic number.

It is an amenable number.

155155221 is a deficient number, since it is larger than the sum of its proper divisors (93925611).

155155221 is a wasteful number, since it uses less digits than its factorization.

155155221 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 394 (or 391 counting only the distinct ones).

The product of its digits is 2500, while the sum is 27.

The square root of 155155221 is about 12456.1318634639. The cubic root of 155155221 is about 537.3477871500.

It can be divided in two parts, 15515 and 5221, that added together give a 4-th power (20736 = 12⁴).

The spelling of 155155221 in words is "one hundred fifty-five million, one hundred fifty-five thousand, two hundred twenty-one".