21259889 has 8 divisors (see below), whose sum is σ = 25353600. Its totient is φ = 17430336.

The previous prime is 21259873. The next prime is 21259891. The reversal of 21259889 is 98895212.

It is a sphenic number, since it is the product of 3 distinct primes.

It is not a de Polignac number, because 21259889 - 2⁴ = 21259873 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (21259829) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 65864 + ... + 66185.

It is an arithmetic number, because the mean of its divisors is an integer number (3169200).

Almost surely, 2^21259889 is an apocalyptic number.

It is an amenable number.

21259889 is a deficient number, since it is larger than the sum of its proper divisors (4093711).

21259889 is a wasteful number, since it uses less digits than its factorization.

21259889 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 132079.

The product of its digits is 103680, while the sum is 44.

The square root of 21259889 is about 4610.8447165351. The cubic root of 21259889 is about 277.0258721984.

The spelling of 21259889 in words is "twenty-one million, two hundred fifty-nine thousand, eight hundred eighty-nine".