21139559 has 16 divisors (see below), whose sum is σ = 25112640. Its totient is φ = 17418240.

The previous prime is 21139513. The next prime is 21139577. The reversal of 21139559 is 95593112.

It is not a de Polignac number, because 21139559 - 2¹⁶ = 21074023 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21139589) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 20447 + ... + 21455.

It is an arithmetic number, because the mean of its divisors is an integer number (1569540).

Almost surely, 2^21139559 is an apocalyptic number.

21139559 is a deficient number, since it is larger than the sum of its proper divisors (3973081).

21139559 is a wasteful number, since it uses less digits than its factorization.

21139559 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1130.

The product of its digits is 12150, while the sum is 35.

The square root of 21139559 is about 4597.7776153268. Note that the first 3 decimals coincide. The cubic root of 21139559 is about 276.5022317672.

The spelling of 21139559 in words is "twenty-one million, one hundred thirty-nine thousand, five hundred fifty-nine".