21124459 has 2 divisors, whose sum is σ = 21124460. Its totient is φ = 21124458.

The previous prime is 21124391. The next prime is 21124463. The reversal of 21124459 is 95442112.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 21124459 - 2¹³ = 21116267 is a prime.

It is a Chen prime.

It is not a weakly prime, because it can be changed into another prime (21124469) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10562229 + 10562230.

It is an arithmetic number, because the mean of its divisors is an integer number (10562230).

Almost surely, 2^21124459 is an apocalyptic number.

21124459 is a deficient number, since it is larger than the sum of its proper divisors (1).

21124459 is an equidigital number, since it uses as much as digits as its factorization.

21124459 is an evil number, because the sum of its binary digits is even.

The product of its digits is 2880, while the sum is 28.

The square root of 21124459 is about 4596.1352242944. The cubic root of 21124459 is about 276.4363808475.

The spelling of 21124459 in words is "twenty-one million, one hundred twenty-four thousand, four hundred fifty-nine".