21884081 has 2 divisors, whose sum is σ = 21884082. Its totient is φ = 21884080.

The previous prime is 21884041. The next prime is 21884089. The reversal of 21884081 is 18048812.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 16200625 + 5683456 = 4025^2 + 2384^2 .

It is a cyclic number.

It is not a de Polignac number, because 21884081 - 2¹⁸ = 21621937 is a prime.

It is a super-2 number, since 2×21884081² = 957826002429122, which contains 22 as substring.

It is not a weakly prime, because it can be changed into another prime (21884089) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10942040 + 10942041.

It is an arithmetic number, because the mean of its divisors is an integer number (10942041).

Almost surely, 2^21884081 is an apocalyptic number.

It is an amenable number.

21884081 is a deficient number, since it is larger than the sum of its proper divisors (1).

21884081 is an equidigital number, since it uses as much as digits as its factorization.

21884081 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 4096, while the sum is 32.

The square root of 21884081 is about 4678.0424324711. The cubic root of 21884081 is about 279.7109304112.

The spelling of 21884081 in words is "twenty-one million, eight hundred eighty-four thousand, eighty-one".