21288559 has 2 divisors, whose sum is σ = 21288560. Its totient is φ = 21288558.

The previous prime is 21288551. The next prime is 21288571. The reversal of 21288559 is 95588212.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 21288559 - 2³ = 21288551 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (21288551) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10644279 + 10644280.

It is an arithmetic number, because the mean of its divisors is an integer number (10644280).

Almost surely, 2^21288559 is an apocalyptic number.

21288559 is a deficient number, since it is larger than the sum of its proper divisors (1).

21288559 is an equidigital number, since it uses as much as digits as its factorization.

21288559 is an evil number, because the sum of its binary digits is even.

The product of its digits is 57600, while the sum is 40.

The square root of 21288559 is about 4613.9526438835. The cubic root of 21288559 is about 277.1503439085.

The spelling of 21288559 in words is "twenty-one million, two hundred eighty-eight thousand, five hundred fifty-nine".