21450839 has 2 divisors, whose sum is σ = 21450840. Its totient is φ = 21450838.

The previous prime is 21450827. The next prime is 21450859. The reversal of 21450839 is 93805412.

It is a weak prime.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-21450839 is a prime.

It is a Chen prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (21450809) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10725419 + 10725420.

It is an arithmetic number, because the mean of its divisors is an integer number (10725420).

Almost surely, 2^21450839 is an apocalyptic number.

21450839 is a deficient number, since it is larger than the sum of its proper divisors (1).

21450839 is an equidigital number, since it uses as much as digits as its factorization.

21450839 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 8640, while the sum is 32.

The square root of 21450839 is about 4631.5050469583. The cubic root of 21450839 is about 277.8527894071.

The spelling of 21450839 in words is "twenty-one million, four hundred fifty thousand, eight hundred thirty-nine".