221050021 has 2 divisors, whose sum is σ = 221050022. Its totient is φ = 221050020.

The previous prime is 221050019. The next prime is 221050061. The reversal of 221050021 is 120050122.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 220968225 + 81796 = 14865^2 + 286^2 .

It is a cyclic number.

It is not a de Polignac number, because 221050021 - 2¹ = 221050019 is a prime.

It is a super-2 number, since 2×221050021² = 97726223568200882, which contains 22 as substring.

Together with 221050019, it forms a pair of twin primes.

It is a Chen prime.

It is a junction number, because it is equal to n+sod(n) for n = 221049983 and 221050010.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (221050001) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 110525010 + 110525011.

It is an arithmetic number, because the mean of its divisors is an integer number (110525011).

Almost surely, 2^221050021 is an apocalyptic number.

It is an amenable number.

221050021 is a deficient number, since it is larger than the sum of its proper divisors (1).

221050021 is an equidigital number, since it uses as much as digits as its factorization.

221050021 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 40, while the sum is 13.

The square root of 221050021 is about 14867.7510404230. The cubic root of 221050021 is about 604.6399706617.

The spelling of 221050021 in words is "two hundred twenty-one million, fifty thousand, twenty-one".