21124887 has 16 divisors (see below), whose sum is σ = 32289792. Its totient is φ = 12034080.

The previous prime is 21124877. The next prime is 21124927. The reversal of 21124887 is 78842112.

It is a happy number.

It is not a de Polignac number, because 21124887 - 2⁴ = 21124871 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21124867) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 6337 + ... + 9077.

It is an arithmetic number, because the mean of its divisors is an integer number (2018112).

Almost surely, 2^21124887 is an apocalyptic number.

21124887 is a deficient number, since it is larger than the sum of its proper divisors (11164905).

21124887 is a wasteful number, since it uses less digits than its factorization.

21124887 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 3118.

The product of its digits is 7168, while the sum is 33.

The square root of 21124887 is about 4596.1817849167. The cubic root of 21124887 is about 276.4382477824.

Adding to 21124887 its reverse (78842112), we get a palindrome (99966999).

The spelling of 21124887 in words is "twenty-one million, one hundred twenty-four thousand, eight hundred eighty-seven".