21479827 has 4 divisors (see below), whose sum is σ = 21565656. Its totient is φ = 21394000.

The previous prime is 21479779. The next prime is 21479839. The reversal of 21479827 is 72897412.

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 21479827 - 2²³ = 13091219 is a prime.

It is a super-2 number, since 2×21479827² = 922765935899858, which contains 22 as substring.

It is a Smith number, since the sum of its digits (40) coincides with the sum of the digits of its prime factors. Since it is squarefree, it is also a hoax number.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 21479827.

It is not an unprimeable number, because it can be changed into a prime (21479027) 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, 42538 + ... + 43039.

It is an arithmetic number, because the mean of its divisors is an integer number (5391414).

Almost surely, 2^21479827 is an apocalyptic number.

21479827 is a deficient number, since it is larger than the sum of its proper divisors (85829).

21479827 is an equidigital number, since it uses as much as digits as its factorization.

21479827 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 85828.

The product of its digits is 56448, while the sum is 40.

The square root of 21479827 is about 4634.6334267124. The cubic root of 21479827 is about 277.9778936237.

The spelling of 21479827 in words is "twenty-one million, four hundred seventy-nine thousand, eight hundred twenty-seven".