21063559 has 6 divisors (see below), whose sum is σ = 23152640. Its totient is φ = 19148580.

The previous prime is 21063529. The next prime is 21063569. The reversal of 21063559 is 95536012.

It is not a de Polignac number, because 21063559 - 2⁹ = 21063047 is a prime.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 21063559.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21063529) by changing a digit.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 86919 + ... + 87160.

Almost surely, 2^21063559 is an apocalyptic number.

21063559 is a deficient number, since it is larger than the sum of its proper divisors (2089081).

21063559 is a wasteful number, since it uses less digits than its factorization.

21063559 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 174101 (or 174090 counting only the distinct ones).

The product of its (nonzero) digits is 8100, while the sum is 31.

The square root of 21063559 is about 4589.5053110330. The cubic root of 21063559 is about 276.1704777146.

It can be divided in two parts, 2106 and 3559, that added together give a palindrome (5665).

The spelling of 21063559 in words is "twenty-one million, sixty-three thousand, five hundred fifty-nine".