155221312 has 56 divisors (see below), whose sum is σ = 318979296. Its totient is φ = 74899968.

The previous prime is 155221289. The next prime is 155221337. The reversal of 155221312 is 213122551.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 226923 + ... + 227605.

Almost surely, 2^155221312 is an apocalyptic number.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 155221312, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (159489648).

155221312 is an abundant number, since it is smaller than the sum of its proper divisors (163757984).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

155221312 is an equidigital number, since it uses as much as digits as its factorization.

155221312 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 815 (or 805 counting only the distinct ones).

The product of its digits is 600, while the sum is 22.

The square root of 155221312 is about 12458.7845314059. The cubic root of 155221312 is about 537.4240737895.

Adding to 155221312 its reverse (213122551), we get a palindrome (368343863).

The spelling of 155221312 in words is "one hundred fifty-five million, two hundred twenty-one thousand, three hundred twelve".