155244221 has 16 divisors (see below), whose sum is σ = 185509440. Its totient is φ = 128244480.

The previous prime is 155244217. The next prime is 155244241. The reversal of 155244221 is 122442551.

155244221 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a cyclic number.

It is not a de Polignac number, because 155244221 - 2² = 155244217 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (155244241) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 8891 + ... + 19736.

It is an arithmetic number, because the mean of its divisors is an integer number (11594340).

Almost surely, 2^155244221 is an apocalyptic number.

155244221 is a gapful number since it is divisible by the number (11) formed by its first and last digit.

It is an amenable number.

155244221 is a deficient number, since it is larger than the sum of its proper divisors (30265219).

155244221 is a wasteful number, since it uses less digits than its factorization.

155244221 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 28684.

The product of its digits is 3200, while the sum is 26.

The square root of 155244221 is about 12459.7038889373. The cubic root of 155244221 is about 537.4505118310.

Adding to 155244221 its reverse (122442551), we get a palindrome (277686772).

The spelling of 155244221 in words is "one hundred fifty-five million, two hundred forty-four thousand, two hundred twenty-one".