21775219 has 2 divisors, whose sum is σ = 21775220. Its totient is φ = 21775218.

The previous prime is 21775207. The next prime is 21775261. The reversal of 21775219 is 91257712.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 21775219 - 2⁹ = 21774707 is a prime.

It is a super-2 number, since 2×21775219² = 948320324995922, which contains 22 as substring.

It is not a weakly prime, because it can be changed into another prime (21775289) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10887609 + 10887610.

It is an arithmetic number, because the mean of its divisors is an integer number (10887610).

Almost surely, 2^21775219 is an apocalyptic number.

21775219 is a deficient number, since it is larger than the sum of its proper divisors (1).

21775219 is an equidigital number, since it uses as much as digits as its factorization.

21775219 is an evil number, because the sum of its binary digits is even.

The product of its digits is 8820, while the sum is 34.

The square root of 21775219 is about 4666.3925038513. The cubic root of 21775219 is about 279.2463534107.

It can be divided in two parts, 2177 and 5219, that added together give a square (7396 = 86²).

The spelling of 21775219 in words is "twenty-one million, seven hundred seventy-five thousand, two hundred nineteen".