21782868 has 24 divisors (see below), whose sum is σ = 51115680. Its totient is φ = 7219680.

The previous prime is 21782861. The next prime is 21782869. The reversal of 21782868 is 86828712.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21782861) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 2923 + ... + 7218.

It is an arithmetic number, because the mean of its divisors is an integer number (2129820).

Almost surely, 2^21782868 is an apocalyptic number.

It is an amenable number.

21782868 is an abundant number, since it is smaller than the sum of its proper divisors (29332812).

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

21782868 is a wasteful number, since it uses less digits than its factorization.

21782868 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 10327 (or 10325 counting only the distinct ones).

The product of its digits is 86016, while the sum is 42.

The square root of 21782868 is about 4667.2120157542. The cubic root of 21782868 is about 279.2790466189.

The spelling of 21782868 in words is "twenty-one million, seven hundred eighty-two thousand, eight hundred sixty-eight".