21043879 has 8 divisors (see below), whose sum is σ = 21867120. Its totient is φ = 20227200.

The previous prime is 21043871. The next prime is 21043901. The reversal of 21043879 is 97834012.

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 21043879 - 2³ = 21043871 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21043871) by changing a digit.

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 in 7 ways as a sum of consecutive naturals, for example, 5484 + ... + 8494.

It is an arithmetic number, because the mean of its divisors is an integer number (2733390).

Almost surely, 2^21043879 is an apocalyptic number.

21043879 is a gapful number since it is divisible by the number (29) formed by its first and last digit.

21043879 is a deficient number, since it is larger than the sum of its proper divisors (823241).

21043879 is a wasteful number, since it uses less digits than its factorization.

21043879 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 3281.

The product of its (nonzero) digits is 12096, while the sum is 34.

The square root of 21043879 is about 4587.3607880785. The cubic root of 21043879 is about 276.0844408368.

The spelling of 21043879 in words is "twenty-one million, forty-three thousand, eight hundred seventy-nine".