155221201 has 2 divisors, whose sum is σ = 155221202. Its totient is φ = 155221200.

The previous prime is 155221163. The next prime is 155221217. The reversal of 155221201 is 102122551.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 109307025 + 45914176 = 10455^2 + 6776^2 .

It is a cyclic number.

It is not a de Polignac number, because 155221201 - 2²⁷ = 21003473 is a prime.

It is not a weakly prime, because it can be changed into another prime (155227201) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 77610600 + 77610601.

It is an arithmetic number, because the mean of its divisors is an integer number (77610601).

Almost surely, 2^155221201 is an apocalyptic number.

It is an amenable number.

155221201 is a deficient number, since it is larger than the sum of its proper divisors (1).

155221201 is an equidigital number, since it uses as much as digits as its factorization.

155221201 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 200, while the sum is 19.

The square root of 155221201 is about 12458.7800767170. The cubic root of 155221201 is about 537.4239456840.

Adding to 155221201 its reverse (102122551), we get a palindrome (257343752).

The spelling of 155221201 in words is "one hundred fifty-five million, two hundred twenty-one thousand, two hundred one".