221387839 has 2 divisors, whose sum is σ = 221387840. Its totient is φ = 221387838.

The previous prime is 221387819. The next prime is 221387863. The reversal of 221387839 is 938783122.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 221387839 - 2²⁵ = 187833407 is a prime.

It is a junction number, because it is equal to n+sod(n) for n = 221387795 and 221387804.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (221387819) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 110693919 + 110693920.

It is an arithmetic number, because the mean of its divisors is an integer number (110693920).

Almost surely, 2^221387839 is an apocalyptic number.

221387839 is a deficient number, since it is larger than the sum of its proper divisors (1).

221387839 is an equidigital number, since it uses as much as digits as its factorization.

221387839 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 145152, while the sum is 43.

The square root of 221387839 is about 14879.1074665116. The cubic root of 221387839 is about 604.9478260223.

The spelling of 221387839 in words is "two hundred twenty-one million, three hundred eighty-seven thousand, eight hundred thirty-nine".