21711879 has 24 divisors (see below), whose sum is σ = 36340512. Its totient is φ = 12234240.

The previous prime is 21711857. The next prime is 21711883. The reversal of 21711879 is 97811712.

It is not a de Polignac number, because 21711879 - 2¹⁹ = 21187591 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21711479) 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 23 ways as a sum of consecutive naturals, for example, 2239 + ... + 6959.

It is an arithmetic number, because the mean of its divisors is an integer number (1514188).

Almost surely, 2^21711879 is an apocalyptic number.

21711879 is a deficient number, since it is larger than the sum of its proper divisors (14628633).

21711879 is a wasteful number, since it uses less digits than its factorization.

21711879 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 4807 (or 4804 counting only the distinct ones).

The product of its digits is 7056, while the sum is 36.

The square root of 21711879 is about 4659.6007339685. The cubic root of 21711879 is about 278.9753321544.

The spelling of 21711879 in words is "twenty-one million, seven hundred eleven thousand, eight hundred seventy-nine".