156413221 has 2 divisors, whose sum is σ = 156413222. Its totient is φ = 156413220.

The previous prime is 156413219. The next prime is 156413249. The reversal of 156413221 is 122314651.

It is a happy number.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 144240100 + 12173121 = 12010^2 + 3489^2 .

It is an emirp because it is prime and its reverse (122314651) is a distict prime.

It is a cyclic number.

It is not a de Polignac number, because 156413221 - 2¹ = 156413219 is a prime.

Together with 156413219, it forms a pair of twin primes.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (156413261) 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 as a sum of consecutive naturals, namely, 78206610 + 78206611.

It is an arithmetic number, because the mean of its divisors is an integer number (78206611).

Almost surely, 2^156413221 is an apocalyptic number.

It is an amenable number.

156413221 is a deficient number, since it is larger than the sum of its proper divisors (1).

156413221 is an equidigital number, since it uses as much as digits as its factorization.

156413221 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 1440, while the sum is 25.

The square root of 156413221 is about 12506.5271358599. The cubic root of 156413221 is about 538.7961533665.

Adding to 156413221 its reverse (122314651), we get a palindrome (278727872).

The spelling of 156413221 in words is "one hundred fifty-six million, four hundred thirteen thousand, two hundred twenty-one".