221231389 has 2 divisors, whose sum is σ = 221231390. Its totient is φ = 221231388.

The previous prime is 221231377. The next prime is 221231393. The reversal of 221231389 is 983132122.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 160858489 + 60372900 = 12683^2 + 7770^2 .

It is a cyclic number.

It is not a de Polignac number, because 221231389 - 2⁵ = 221231357 is a prime.

It is a self number, because there is not a number n which added to its sum of digits gives 221231389.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (221331389) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 110615694 + 110615695.

It is an arithmetic number, because the mean of its divisors is an integer number (110615695).

Almost surely, 2^221231389 is an apocalyptic number.

It is an amenable number.

221231389 is a deficient number, since it is larger than the sum of its proper divisors (1).

221231389 is an equidigital number, since it uses as much as digits as its factorization.

221231389 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 5184, while the sum is 31.

The square root of 221231389 is about 14873.8491655657. The cubic root of 221231389 is about 604.8052912579.

The spelling of 221231389 in words is "two hundred twenty-one million, two hundred thirty-one thousand, three hundred eighty-nine".