21895679 has 4 divisors (see below), whose sum is σ = 23579976. Its totient is φ = 20211384.

The previous prime is 21895669. The next prime is 21895721. The reversal of 21895679 is 97659812.

It is a semiprime because it is the product of two primes.

It is a cyclic number.

It is not a de Polignac number, because 21895679 - 2⁴ = 21895663 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 (21895639) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 842129 + ... + 842154.

It is an arithmetic number, because the mean of its divisors is an integer number (5894994).

Almost surely, 2^21895679 is an apocalyptic number.

21895679 is a deficient number, since it is larger than the sum of its proper divisors (1684297).

21895679 is a wasteful number, since it uses less digits than its factorization.

21895679 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1684296.

The product of its digits is 272160, while the sum is 47.

The square root of 21895679 is about 4679.2818893501. The cubic root of 21895679 is about 279.7603348839.

The spelling of 21895679 in words is "twenty-one million, eight hundred ninety-five thousand, six hundred seventy-nine".