21885289 has 2 divisors, whose sum is σ = 21885290. Its totient is φ = 21885288.

The previous prime is 21885277. The next prime is 21885299. The reversal of 21885289 is 98258812.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 11594025 + 10291264 = 3405^2 + 3208^2 .

It is a cyclic number.

It is not a de Polignac number, because 21885289 - 2⁵ = 21885257 is a prime.

It is a super-2 number, since 2×21885289² = 957931749227042, which contains 22 as substring.

It is not a weakly prime, because it can be changed into another prime (21885229) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10942644 + 10942645.

It is an arithmetic number, because the mean of its divisors is an integer number (10942645).

Almost surely, 2^21885289 is an apocalyptic number.

It is an amenable number.

21885289 is a deficient number, since it is larger than the sum of its proper divisors (1).

21885289 is an equidigital number, since it uses as much as digits as its factorization.

21885289 is an evil number, because the sum of its binary digits is even.

The product of its digits is 92160, while the sum is 43.

The square root of 21885289 is about 4678.1715445246. The cubic root of 21885289 is about 279.7160769923.

The spelling of 21885289 in words is "twenty-one million, eight hundred eighty-five thousand, two hundred eighty-nine".