21719268 has 72 divisors (see below), whose sum is σ = 60697728. Its totient is φ = 6513408.

The previous prime is 21719267. The next prime is 21719273. The reversal of 21719268 is 86291712.

It is a Smith number, since the sum of its digits (36) coincides with the sum of the digits of its prime factors.

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

It is not an unprimeable number, because it can be changed into a prime (21719263) by changing a digit.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 13305 + ... + 14847.

It is an arithmetic number, because the mean of its divisors is an integer number (843024).

Almost surely, 2^21719268 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 21719268, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (30348864).

21719268 is an abundant number, since it is smaller than the sum of its proper divisors (38978460).

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

21719268 is a wasteful number, since it uses less digits than its factorization.

21719268 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1593 (or 1588 counting only the distinct ones).

The product of its digits is 12096, while the sum is 36.

The square root of 21719268 is about 4660.3935456139. The cubic root of 21719268 is about 279.0069755839.

The spelling of 21719268 in words is "twenty-one million, seven hundred nineteen thousand, two hundred sixty-eight".