21988823 has 2 divisors, whose sum is σ = 21988824. Its totient is φ = 21988822.

The previous prime is 21988801. The next prime is 21988829. The reversal of 21988823 is 32888912.

It is a happy number.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 21988823 - 2¹⁰ = 21987799 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (21988829) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10994411 + 10994412.

It is an arithmetic number, because the mean of its divisors is an integer number (10994412).

Almost surely, 2^21988823 is an apocalyptic number.

21988823 is a deficient number, since it is larger than the sum of its proper divisors (1).

21988823 is an equidigital number, since it uses as much as digits as its factorization.

21988823 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 55296, while the sum is 41.

The square root of 21988823 is about 4689.2241362511. The cubic root of 21988823 is about 280.1564729158.

The spelling of 21988823 in words is "twenty-one million, nine hundred eighty-eight thousand, eight hundred twenty-three".