21559659 has 12 divisors (see below), whose sum is σ = 31597608. Its totient is φ = 13066240.

The previous prime is 21559649. The next prime is 21559667. The reversal of 21559659 is 95695512.

It is not a de Polignac number, because 21559659 - 2²⁰ = 20511083 is a prime.

It is a self number, because there is not a number n which added to its sum of digits gives 21559659.

It is not an unprimeable number, because it can be changed into a prime (21559639) by changing a digit.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 29334 + ... + 30059.

It is an arithmetic number, because the mean of its divisors is an integer number (2633134).

Almost surely, 2^21559659 is an apocalyptic number.

21559659 is a deficient number, since it is larger than the sum of its proper divisors (10037949).

21559659 is a wasteful number, since it uses less digits than its factorization.

21559659 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 59418 (or 59407 counting only the distinct ones).

The product of its digits is 121500, while the sum is 42.

The square root of 21559659 is about 4643.2379865779. The cubic root of 21559659 is about 278.3218457337.

The spelling of 21559659 in words is "twenty-one million, five hundred fifty-nine thousand, six hundred fifty-nine".