21828079 has 12 divisors (see below), whose sum is σ = 27345864. Its totient is φ = 17270064.

The previous prime is 21828077. The next prime is 21828083. The reversal of 21828079 is 97082812.

It is not a de Polignac number, because 21828079 - 2¹ = 21828077 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21828071) by changing a digit.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 16497 + ... + 17770.

It is an arithmetic number, because the mean of its divisors is an integer number (2278822).

Almost surely, 2^21828079 is an apocalyptic number.

21828079 is a deficient number, since it is larger than the sum of its proper divisors (5517785).

21828079 is a wasteful number, since it uses less digits than its factorization.

21828079 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 34294 (or 34287 counting only the distinct ones).

The product of its (nonzero) digits is 16128, while the sum is 37.

The square root of 21828079 is about 4672.0529748709. The cubic root of 21828079 is about 279.4721304602.

It can be divided in two parts, 21 and 828079, that added together give a square (828100 = 910²).

The spelling of 21828079 in words is "twenty-one million, eight hundred twenty-eight thousand, seventy-nine".