221644091 has 2 divisors, whose sum is σ = 221644092. Its totient is φ = 221644090.

The previous prime is 221644069. The next prime is 221644099. The reversal of 221644091 is 190446122.

221644091 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 221644091 - 2¹⁸ = 221381947 is a prime.

It is a super-2 number, since 2×221644091² = 98252206150432562, which contains 22 as substring.

It is not a weakly prime, because it can be changed into another prime (221644099) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 110822045 + 110822046.

It is an arithmetic number, because the mean of its divisors is an integer number (110822046).

Almost surely, 2^221644091 is an apocalyptic number.

221644091 is a deficient number, since it is larger than the sum of its proper divisors (1).

221644091 is an equidigital number, since it uses as much as digits as its factorization.

221644091 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 3456, while the sum is 29.

The square root of 221644091 is about 14887.7161109419. The cubic root of 221644091 is about 605.1811410333.

The spelling of 221644091 in words is "two hundred twenty-one million, six hundred forty-four thousand, ninety-one".