21919356 has 48 divisors (see below), whose sum is σ = 58670080. Its totient is φ = 7069680.

The previous prime is 21919349. The next prime is 21919357. The reversal of 21919356 is 65391912.

It is a Harshad number since it is a multiple of its sum of digits (36).

It is a self number, because there is not a number n which added to its sum of digits gives 21919356.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21919357) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 75 + ... + 6621.

Almost surely, 2^21919356 is an apocalyptic number.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 21919356, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (29335040).

21919356 is an abundant number, since it is smaller than the sum of its proper divisors (36750724).

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

21919356 is a wasteful number, since it uses less digits than its factorization.

21919356 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 6591 (or 6583 counting only the distinct ones).

The product of its digits is 14580, while the sum is 36.

The square root of 21919356 is about 4681.8111879912. The cubic root of 21919356 is about 279.8611386284.

The spelling of 21919356 in words is "twenty-one million, nine hundred nineteen thousand, three hundred fifty-six".