221623811 has 2 divisors, whose sum is σ = 221623812. Its totient is φ = 221623810.

The previous prime is 221623799. The next prime is 221623813. The reversal of 221623811 is 118326122.

221623811 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 221623811 - 2¹⁸ = 221361667 is a prime.

It is a super-2 number, since 2×221623811² = 98234227204327442, which contains 22 as substring.

Together with 221623813, it forms a pair of twin primes.

It is a Chen prime.

It is not a weakly prime, because it can be changed into another prime (221623813) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 110811905 + 110811906.

It is an arithmetic number, because the mean of its divisors is an integer number (110811906).

Almost surely, 2^221623811 is an apocalyptic number.

221623811 is a deficient number, since it is larger than the sum of its proper divisors (1).

221623811 is an equidigital number, since it uses as much as digits as its factorization.

221623811 is an evil number, because the sum of its binary digits is even.

The product of its digits is 1152, while the sum is 26.

The square root of 221623811 is about 14887.0349969361. The cubic root of 221623811 is about 605.1626828408.

Adding to 221623811 its reverse (118326122), we get a palindrome (339949933).

The spelling of 221623811 in words is "two hundred twenty-one million, six hundred twenty-three thousand, eight hundred eleven".