21785968 has 40 divisors (see below), whose sum is σ = 44916768. Its totient is φ = 10213632.

The previous prime is 21785947. The next prime is 21785969. The reversal of 21785968 is 86958712.

It is a Harshad number since it is a multiple of its sum of digits (46).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21785969) 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, 18946 + ... + 20062.

Almost surely, 2^21785968 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 21785968, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (22458384).

21785968 is an abundant number, since it is smaller than the sum of its proper divisors (23130800).

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

21785968 is a wasteful number, since it uses less digits than its factorization.

21785968 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1201 (or 1195 counting only the distinct ones).

The product of its digits is 241920, while the sum is 46.

The square root of 21785968 is about 4667.5441079866. The cubic root of 21785968 is about 279.2922943996.

The spelling of 21785968 in words is "twenty-one million, seven hundred eighty-five thousand, nine hundred sixty-eight".