21868679 has 8 divisors (see below), whose sum is σ = 25061760. Its totient is φ = 18692856.

The previous prime is 21868669. The next prime is 21868709. The reversal of 21868679 is 97686812.

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

It is a de Polignac number, because none of the positive numbers 2^k-21868679 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 (21868619) 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, 1469 + ... + 6774.

It is an arithmetic number, because the mean of its divisors is an integer number (3132720).

Almost surely, 2^21868679 is an apocalyptic number.

21868679 is a deficient number, since it is larger than the sum of its proper divisors (3193081).

21868679 is an equidigital number, since it uses as much as digits as its factorization.

21868679 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 8629.

The product of its digits is 290304, while the sum is 47.

The square root of 21868679 is about 4676.3959413206. The cubic root of 21868679 is about 279.6452948955.

It can be divided in two parts, 2 and 1868679, that added together give a palindrome (1868681).

The spelling of 21868679 in words is "twenty-one million, eight hundred sixty-eight thousand, six hundred seventy-nine".