221853421 has 2 divisors, whose sum is σ = 221853422. Its totient is φ = 221853420.

The previous prime is 221853407. The next prime is 221853431. The reversal of 221853421 is 124358122.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 188375625 + 33477796 = 13725^2 + 5786^2 .

It is a cyclic number.

It is not a de Polignac number, because 221853421 - 2⁷ = 221853293 is a prime.

It is a super-5 number, since 5×221853421⁵ (a number of 43 digits) contains 55555 as substring.

It is a self number, because there is not a number n which added to its sum of digits gives 221853421.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (221853431) 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, 110926710 + 110926711.

It is an arithmetic number, because the mean of its divisors is an integer number (110926711).

Almost surely, 2^221853421 is an apocalyptic number.

It is an amenable number.

221853421 is a deficient number, since it is larger than the sum of its proper divisors (1).

221853421 is an equidigital number, since it uses as much as digits as its factorization.

221853421 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 3840, while the sum is 28.

The square root of 221853421 is about 14894.7447443721. The cubic root of 221853421 is about 605.3716005927.

The spelling of 221853421 in words is "two hundred twenty-one million, eight hundred fifty-three thousand, four hundred twenty-one".