21968305 has 8 divisors (see below), whose sum is σ = 27212544. Its totient is φ = 17007600.

The previous prime is 21968293. The next prime is 21968321. The reversal of 21968305 is 50386912.

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

It is not a de Polignac number, because 21968305 - 2⁹ = 21967793 is a prime.

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 70711 + ... + 71020.

It is an arithmetic number, because the mean of its divisors is an integer number (3401568).

Almost surely, 2^21968305 is an apocalyptic number.

It is an amenable number.

21968305 is a deficient number, since it is larger than the sum of its proper divisors (5244239).

21968305 is a wasteful number, since it uses less digits than its factorization.

21968305 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 141767.

The product of its (nonzero) digits is 12960, while the sum is 34.

The square root of 21968305 is about 4687.0358436863. The cubic root of 21968305 is about 280.0693068230.

It can be divided in two parts, 2196 and 8305, that multiplied together give a triangular number (18237780 = T₆₀₃₉).

The spelling of 21968305 in words is "twenty-one million, nine hundred sixty-eight thousand, three hundred five".