21440579 has 2 divisors, whose sum is σ = 21440580. Its totient is φ = 21440578.

The previous prime is 21440539. The next prime is 21440593. The reversal of 21440579 is 97504412.

It is a happy number.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 21440579 - 2¹⁶ = 21375043 is a prime.

It is a Sophie Germain prime.

It is not a weakly prime, because it can be changed into another prime (21440539) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10720289 + 10720290.

It is an arithmetic number, because the mean of its divisors is an integer number (10720290).

Almost surely, 2^21440579 is an apocalyptic number.

21440579 is a deficient number, since it is larger than the sum of its proper divisors (1).

21440579 is an equidigital number, since it uses as much as digits as its factorization.

21440579 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 10080, while the sum is 32.

The square root of 21440579 is about 4630.3972831713. The cubic root of 21440579 is about 277.8084830709.

The spelling of 21440579 in words is "twenty-one million, four hundred forty thousand, five hundred seventy-nine".