21968013 has 8 divisors (see below), whose sum is σ = 30564288. Its totient is φ = 14008544.

The previous prime is 21968003. The next prime is 21968053. The reversal of 21968013 is 31086912.

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

It is a cyclic number.

It is not a de Polignac number, because 21968013 - 2¹² = 21963917 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21968003) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 159120 + ... + 159257.

It is an arithmetic number, because the mean of its divisors is an integer number (3820536).

Almost surely, 2^21968013 is an apocalyptic number.

21968013 is a gapful number since it is divisible by the number (23) formed by its first and last digit.

It is an amenable number.

21968013 is a deficient number, since it is larger than the sum of its proper divisors (8596275).

21968013 is a wasteful number, since it uses less digits than its factorization.

21968013 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 318403.

The product of its (nonzero) digits is 2592, while the sum is 30.

The square root of 21968013 is about 4687.0046938317. The cubic root of 21968013 is about 280.0680659353.

The spelling of 21968013 in words is "twenty-one million, nine hundred sixty-eight thousand, thirteen".