155010221 has 4 divisors (see below), whose sum is σ = 155426172. Its totient is φ = 154594272.

The previous prime is 155010209. The next prime is 155010239. The reversal of 155010221 is 122010551.

155010221 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 129709321 + 25300900 = 11389^2 + 5030^2 .

It is a cyclic number.

It is not a de Polignac number, because 155010221 - 2¹⁴ = 154993837 is a prime.

It is a super-2 number, since 2×155010221² = 48056337228937682, which contains 22 as substring.

It is a Duffinian number.

It is a Curzon number.

It is a self number, because there is not a number n which added to its sum of digits gives 155010221.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (155010281) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 207416 + ... + 208161.

It is an arithmetic number, because the mean of its divisors is an integer number (38856543).

Almost surely, 2^155010221 is an apocalyptic number.

It is an amenable number.

155010221 is a deficient number, since it is larger than the sum of its proper divisors (415951).

155010221 is an equidigital number, since it uses as much as digits as its factorization.

155010221 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 415950.

The product of its (nonzero) digits is 100, while the sum is 17.

The square root of 155010221 is about 12450.3100764599. The cubic root of 155010221 is about 537.1803425459.

Adding to 155010221 its reverse (122010551), we get a palindrome (277020772).

The spelling of 155010221 in words is "one hundred fifty-five million, ten thousand, two hundred twenty-one".