155221145 has 8 divisors (see below), whose sum is σ = 186902856. Its totient is φ = 123751936.

The previous prime is 155221133. The next prime is 155221159. The reversal of 155221145 is 541122551.

It can be written as a sum of positive squares in 4 ways, for example, as 11916304 + 143304841 = 3452^2 + 11971^2 .

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

It is a cyclic number.

It is not a de Polignac number, because 155221145 - 2⁸ = 155220889 is a prime.

It is a super-2 number, since 2×155221145² = 48187207710222050, which contains 22 as substring.

It is a Duffinian 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, 51512 + ... + 54441.

It is an arithmetic number, because the mean of its divisors is an integer number (23362857).

Almost surely, 2^155221145 is an apocalyptic number.

It is an amenable number.

155221145 is a deficient number, since it is larger than the sum of its proper divisors (31681711).

155221145 is a wasteful number, since it uses less digits than its factorization.

155221145 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 106251.

The product of its digits is 2000, while the sum is 26.

The square root of 155221145 is about 12458.7778293057. Note that the first 3 decimals coincide. The cubic root of 155221145 is about 537.4238810542.

Adding to 155221145 its reverse (541122551), we get a palindrome (696343696).

The spelling of 155221145 in words is "one hundred fifty-five million, two hundred twenty-one thousand, one hundred forty-five".