21735859 has 2 divisors, whose sum is σ = 21735860. Its totient is φ = 21735858.

The previous prime is 21735841. The next prime is 21735919. The reversal of 21735859 is 95853712.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 21735859 - 2¹⁷ = 21604787 is a prime.

It is not a weakly prime, because it can be changed into another prime (21735839) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10867929 + 10867930.

It is an arithmetic number, because the mean of its divisors is an integer number (10867930).

Almost surely, 2^21735859 is an apocalyptic number.

21735859 is a deficient number, since it is larger than the sum of its proper divisors (1).

21735859 is an equidigital number, since it uses as much as digits as its factorization.

21735859 is an evil number, because the sum of its binary digits is even.

The product of its digits is 75600, while the sum is 40.

The square root of 21735859 is about 4662.1732057057. The cubic root of 21735859 is about 279.0780004846.

The spelling of 21735859 in words is "twenty-one million, seven hundred thirty-five thousand, eight hundred fifty-nine".