21938826 has 64 divisors (see below), whose sum is σ = 56383488. Its totient is φ = 5531328.

The previous prime is 21938779. The next prime is 21938831. The reversal of 21938826 is 62883912.

It is a happy number.

It is a Harshad number since it is a multiple of its sum of digits (39).

It is a Curzon number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 11685 + ... + 13431.

It is an arithmetic number, because the mean of its divisors is an integer number (880992).

Almost surely, 2^21938826 is an apocalyptic number.

21938826 is a gapful number since it is divisible by the number (26) formed by its first and last digit.

It is a practical number, because each smaller number is the sum of distinct divisors of 21938826, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (28191744).

21938826 is an abundant number, since it is smaller than the sum of its proper divisors (34444662).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

21938826 is a wasteful number, since it uses less digits than its factorization.

21938826 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1795.

The product of its digits is 41472, while the sum is 39.

The square root of 21938826 is about 4683.8900499478. The cubic root of 21938826 is about 279.9439768867.

The spelling of 21938826 in words is "twenty-one million, nine hundred thirty-eight thousand, eight hundred twenty-six".