155221445 has 4 divisors (see below), whose sum is σ = 186265740. Its totient is φ = 124177152.

The previous prime is 155221399. The next prime is 155221459. The reversal of 155221445 is 544122551.

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 28366276 + 126855169 = 5326^2 + 11263^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-155221445 is a prime.

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 15522140 + ... + 15522149.

It is an arithmetic number, because the mean of its divisors is an integer number (46566435).

Almost surely, 2^155221445 is an apocalyptic number.

It is an amenable number.

155221445 is a deficient number, since it is larger than the sum of its proper divisors (31044295).

155221445 is an equidigital number, since it uses as much as digits as its factorization.

155221445 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 31044294.

The product of its digits is 8000, while the sum is 29.

The square root of 155221445 is about 12458.7898690041. The cubic root of 155221445 is about 537.4242272851.

Adding to 155221445 its reverse (544122551), we get a palindrome (699343996).

The spelling of 155221445 in words is "one hundred fifty-five million, two hundred twenty-one thousand, four hundred forty-five".