21827489 has 2 divisors, whose sum is σ = 21827490. Its totient is φ = 21827488.

The previous prime is 21827479. The next prime is 21827497. The reversal of 21827489 is 98472812.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 21160000 + 667489 = 4600^2 + 817^2 .

It is a cyclic number.

It is not a de Polignac number, because 21827489 - 2⁸ = 21827233 is a prime.

It is not a weakly prime, because it can be changed into another prime (21827479) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10913744 + 10913745.

It is an arithmetic number, because the mean of its divisors is an integer number (10913745).

Almost surely, 2^21827489 is an apocalyptic number.

It is an amenable number.

21827489 is a deficient number, since it is larger than the sum of its proper divisors (1).

21827489 is an equidigital number, since it uses as much as digits as its factorization.

21827489 is an evil number, because the sum of its binary digits is even.

The product of its digits is 64512, while the sum is 41.

The square root of 21827489 is about 4671.9898330369. The cubic root of 21827489 is about 279.4696124490.

The spelling of 21827489 in words is "twenty-one million, eight hundred twenty-seven thousand, four hundred eighty-nine".