21417879 has 8 divisors (see below), whose sum is σ = 32636800. Its totient is φ = 12238776.

The previous prime is 21417871. The next prime is 21417889. The reversal of 21417879 is 97871412.

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

It is not a de Polignac number, because 21417879 - 2³ = 21417871 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21417871) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 509929 + ... + 509970.

It is an arithmetic number, because the mean of its divisors is an integer number (4079600).

Almost surely, 2^21417879 is an apocalyptic number.

21417879 is a deficient number, since it is larger than the sum of its proper divisors (11218921).

21417879 is a wasteful number, since it uses less digits than its factorization.

21417879 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1019909.

The product of its digits is 28224, while the sum is 39.

The square root of 21417879 is about 4627.9454404736. The cubic root of 21417879 is about 277.7104061263.

The spelling of 21417879 in words is "twenty-one million, four hundred seventeen thousand, eight hundred seventy-nine".