221151913 has 2 divisors, whose sum is σ = 221151914. Its totient is φ = 221151912.

The previous prime is 221151911. The next prime is 221151937. The reversal of 221151913 is 319151122.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 192987664 + 28164249 = 13892^2 + 5307^2 .

It is a cyclic number.

It is not a de Polignac number, because 221151913 - 2¹ = 221151911 is a prime.

Together with 221151911, it forms a pair of twin primes.

It is not a weakly prime, because it can be changed into another prime (221151911) 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, 110575956 + 110575957.

It is an arithmetic number, because the mean of its divisors is an integer number (110575957).

Almost surely, 2^221151913 is an apocalyptic number.

It is an amenable number.

221151913 is a deficient number, since it is larger than the sum of its proper divisors (1).

221151913 is an equidigital number, since it uses as much as digits as its factorization.

221151913 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 540, while the sum is 25.

The square root of 221151913 is about 14871.1772566936. The cubic root of 221151913 is about 604.7328584043.

The spelling of 221151913 in words is "two hundred twenty-one million, one hundred fifty-one thousand, nine hundred thirteen".