21124859 has 4 divisors (see below), whose sum is σ = 24142704. Its totient is φ = 18107016.

The previous prime is 21124853. The next prime is 21124867. The reversal of 21124859 is 95842112.

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

It is a cyclic number.

It is not a de Polignac number, because 21124859 - 2¹² = 21120763 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (21124853) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 1508912 + ... + 1508925.

It is an arithmetic number, because the mean of its divisors is an integer number (6035676).

Almost surely, 2^21124859 is an apocalyptic number.

21124859 is a deficient number, since it is larger than the sum of its proper divisors (3017845).

21124859 is an equidigital number, since it uses as much as digits as its factorization.

21124859 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 3017844.

The product of its digits is 5760, while the sum is 32.

The square root of 21124859 is about 4596.1787389091. The cubic root of 21124859 is about 276.4381256473.

The spelling of 21124859 in words is "twenty-one million, one hundred twenty-four thousand, eight hundred fifty-nine".