156405221321 has 2 divisors, whose sum is σ = 156405221322. Its totient is φ = 156405221320.

The previous prime is 156405221263. The next prime is 156405221327. The reversal of 156405221321 is 123122504651.

156405221321 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 102951781321 + 53453440000 = 320861^2 + 231200^2 .

It is an emirp because it is prime and its reverse (123122504651) is a distict prime.

It is a cyclic number.

It is not a de Polignac number, because 156405221321 - 2²² = 156401027017 is a prime.

It is not a weakly prime, because it can be changed into another prime (156405221327) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 78202610660 + 78202610661.

It is an arithmetic number, because the mean of its divisors is an integer number (78202610661).

Almost surely, 2^156405221321 is an apocalyptic number.

It is an amenable number.

156405221321 is a deficient number, since it is larger than the sum of its proper divisors (1).

156405221321 is an equidigital number, since it uses as much as digits as its factorization.

156405221321 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 14400, while the sum is 32.

Adding to 156405221321 its reverse (123122504651), we get a palindrome (279527725972).

The spelling of 156405221321 in words is "one hundred fifty-six billion, four hundred five million, two hundred twenty-one thousand, three hundred twenty-one".