21289359 has 16 divisors (see below), whose sum is σ = 34936832. Its totient is φ = 11229408.

The previous prime is 21289337. The next prime is 21289361. The reversal of 21289359 is 95398212.

It is not a de Polignac number, because 21289359 - 2¹⁵ = 21256591 is a prime.

It is a Harshad number since it is a multiple of its sum of digits (39).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21289369) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 38719 + ... + 39264.

It is an arithmetic number, because the mean of its divisors is an integer number (2183552).

Almost surely, 2^21289359 is an apocalyptic number.

21289359 is a deficient number, since it is larger than the sum of its proper divisors (13647473).

21289359 is a wasteful number, since it uses less digits than its factorization.

21289359 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 78006.

The product of its digits is 38880, while the sum is 39.

The square root of 21289359 is about 4614.0393366334. The cubic root of 21289359 is about 277.1538155306.

The spelling of 21289359 in words is "twenty-one million, two hundred eighty-nine thousand, three hundred fifty-nine".