155927221 has 4 divisors (see below), whose sum is σ = 155954700. Its totient is φ = 155899744.

The previous prime is 155927207. The next prime is 155927227. The reversal of 155927221 is 122729551.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 122729551 = 7 ⋅17532793.

It can be written as a sum of positive squares in 2 ways, for example, as 79014321 + 76912900 = 8889^2 + 8770^2 .

It is a cyclic number.

It is not a de Polignac number, because 155927221 - 2⁹ = 155926709 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (155927227) by changing a digit.

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, 1726 + ... + 17743.

It is an arithmetic number, because the mean of its divisors is an integer number (38988675).

Almost surely, 2^155927221 is an apocalyptic number.

It is an amenable number.

155927221 is a deficient number, since it is larger than the sum of its proper divisors (27479).

155927221 is an equidigital number, since it uses as much as digits as its factorization.

155927221 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 27478.

The product of its digits is 12600, while the sum is 34.

The square root of 155927221 is about 12487.0821651817. The cubic root of 155927221 is about 538.2375334794.

The spelling of 155927221 in words is "one hundred fifty-five million, nine hundred twenty-seven thousand, two hundred twenty-one".