21559042 has 4 divisors (see below), whose sum is σ = 32338566. Its totient is φ = 10779520.

The previous prime is 21559037. The next prime is 21559061. The reversal of 21559042 is 24095512.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in only one way, i.e., 16088121 + 5470921 = 4011^2 + 2339^2 .

It is a self number, because there is not a number n which added to its sum of digits gives 21559042.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 5389759 + ... + 5389762.

Almost surely, 2^21559042 is an apocalyptic number.

21559042 is a deficient number, since it is larger than the sum of its proper divisors (10779524).

21559042 is a wasteful number, since it uses less digits than its factorization.

21559042 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 10779523.

The product of its (nonzero) digits is 3600, while the sum is 28.

The square root of 21559042 is about 4643.1715453987. The cubic root of 21559042 is about 278.3191906790.

The spelling of 21559042 in words is "twenty-one million, five hundred fifty-nine thousand, forty-two".