21828823 has 2 divisors, whose sum is σ = 21828824. Its totient is φ = 21828822.

The previous prime is 21828803. The next prime is 21828839. The reversal of 21828823 is 32882812.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 21828823 - 2⁵ = 21828791 is a prime.

It is a super-3 number, since 3×21828823³ (a number of 23 digits) contains 333 as substring.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (21828803) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10914411 + 10914412.

It is an arithmetic number, because the mean of its divisors is an integer number (10914412).

Almost surely, 2^21828823 is an apocalyptic number.

21828823 is a deficient number, since it is larger than the sum of its proper divisors (1).

21828823 is an equidigital number, since it uses as much as digits as its factorization.

21828823 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 12288, while the sum is 34.

The square root of 21828823 is about 4672.1325965773. The cubic root of 21828823 is about 279.4753056503.

The spelling of 21828823 in words is "twenty-one million, eight hundred twenty-eight thousand, eight hundred twenty-three".