21159587 has 2 divisors, whose sum is σ = 21159588. Its totient is φ = 21159586.

The previous prime is 21159539. The next prime is 21159613. The reversal of 21159587 is 78595112.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 21159587 - 2¹⁰ = 21158563 is a prime.

It is a self number, because there is not a number n which added to its sum of digits gives 21159587.

It is not a weakly prime, because it can be changed into another prime (21159527) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a good prime.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10579793 + 10579794.

It is an arithmetic number, because the mean of its divisors is an integer number (10579794).

Almost surely, 2^21159587 is an apocalyptic number.

21159587 is a deficient number, since it is larger than the sum of its proper divisors (1).

21159587 is an equidigital number, since it uses as much as digits as its factorization.

21159587 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 25200, while the sum is 38.

The square root of 21159587 is about 4599.9551084766. The cubic root of 21159587 is about 276.5895252746.

The spelling of 21159587 in words is "twenty-one million, one hundred fifty-nine thousand, five hundred eighty-seven".