155213121 has 8 divisors (see below), whose sum is σ = 236515264. Its totient is φ = 88693200.

The previous prime is 155213119. The next prime is 155213141. The reversal of 155213121 is 121312551.

It is a sphenic number, since it is the product of 3 distinct primes.

It is not a de Polignac number, because 155213121 - 2¹ = 155213119 is a prime.

It is a super-2 number, since 2×155213121² = 48182225861121282, which contains 22 as substring.

It is a Harshad number since it is a multiple of its sum of digits (21), and also a Moran number because the ratio is a prime number: 7391101 = 155213121 / (1 + 5 + 5 + 2 + 1 + 3 + 1 + 2 + 1).

It is a Duffinian number.

It is a Curzon number.

It is not an unprimeable number, because it can be changed into a prime (155213141) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 3695530 + ... + 3695571.

It is an arithmetic number, because the mean of its divisors is an integer number (29564408).

Almost surely, 2^155213121 is an apocalyptic number.

It is an amenable number.

155213121 is a deficient number, since it is larger than the sum of its proper divisors (81302143).

155213121 is an equidigital number, since it uses as much as digits as its factorization.

155213121 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 7391111.

The product of its digits is 300, while the sum is 21.

The square root of 155213121 is about 12458.4558031885. The cubic root of 155213121 is about 537.4146203668.

Adding to 155213121 its reverse (121312551), we get a palindrome (276525672).

The spelling of 155213121 in words is "one hundred fifty-five million, two hundred thirteen thousand, one hundred twenty-one".