21968018 has 8 divisors (see below), whose sum is σ = 33070140. Its totient is φ = 10944640.

The previous prime is 21968003. The next prime is 21968053. The reversal of 21968018 is 81086912.

It can be written as a sum of positive squares in 2 ways, for example, as 21967969 + 49 = 4687^2 + 7^2 .

It is a sphenic number, since it is the product of 3 distinct primes.

It is an unprimeable number.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 18983 + ... + 20106.

Almost surely, 2^21968018 is an apocalyptic number.

21968018 is a deficient number, since it is larger than the sum of its proper divisors (11102122).

21968018 is a wasteful number, since it uses less digits than its factorization.

21968018 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 39372.

The product of its (nonzero) digits is 6912, while the sum is 35.

The square root of 21968018 is about 4687.0052272213. The cubic root of 21968018 is about 280.0680871835.

The spelling of 21968018 in words is "twenty-one million, nine hundred sixty-eight thousand, eighteen".