21968000 has 64 divisors (see below), whose sum is σ = 54657720. Its totient is φ = 8780800.

The previous prime is 21967987. The next prime is 21968003. The reversal of 21968000 is 86912.

It can be written as a sum of positive squares in 4 ways, for example, as 13719616 + 8248384 = 3704^2 + 2872^2 .

It is a tau number, because it is divible by the number of its divisors (64).

It is not an unprimeable number, because it can be changed into a prime (21968003) 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, 15314 + ... + 16686.

Almost surely, 2^21968000 is an apocalyptic number.

21968000 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 21968000, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (27328860).

21968000 is an abundant number, since it is smaller than the sum of its proper divisors (32689720).

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

21968000 is an equidigital number, since it uses as much as digits as its factorization.

21968000 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1402 (or 1380 counting only the distinct ones).

The product of its (nonzero) digits is 864, while the sum is 26.

The square root of 21968000 is about 4687.0033070182. The cubic root of 21968000 is about 280.0680106901.

The spelling of 21968000 in words is "twenty-one million, nine hundred sixty-eight thousand".