21968331 has 16 divisors (see below), whose sum is σ = 36519168. Its totient is φ = 11412000.

The previous prime is 21968321. The next prime is 21968347. The reversal of 21968331 is 13386912.

It is not a de Polignac number, because 21968331 - 2⁷ = 21968203 is a prime.

It is a super-2 number, since 2×21968331² = 965215133851122, which contains 22 as substring.

It is a Harshad number since it is a multiple of its sum of digits (33).

It is a junction number, because it is equal to n+sod(n) for n = 21968292 and 21968301.

It is not an unprimeable number, because it can be changed into a prime (21968321) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 47320 + ... + 47781.

It is an arithmetic number, because the mean of its divisors is an integer number (2282448).

Almost surely, 2^21968331 is an apocalyptic number.

21968331 is a gapful number since it is divisible by the number (21) formed by its first and last digit.

21968331 is a deficient number, since it is larger than the sum of its proper divisors (14550837).

21968331 is a wasteful number, since it uses less digits than its factorization.

21968331 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 95122.

The product of its digits is 7776, while the sum is 33.

The square root of 21968331 is about 4687.0386172934. The cubic root of 21968331 is about 280.0694173125.

The spelling of 21968331 in words is "twenty-one million, nine hundred sixty-eight thousand, three hundred thirty-one".