21168745 has 8 divisors (see below), whose sum is σ = 27356616. Its totient is φ = 15632256.

The previous prime is 21168713. The next prime is 21168767. The reversal of 21168745 is 54786112.

It can be written as a sum of positive squares in 4 ways, for example, as 183184 + 20985561 = 428^2 + 4581^2 .

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 21168745 - 2⁵ = 21168713 is a prime.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 21168745.

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, 162772 + ... + 162901.

It is an arithmetic number, because the mean of its divisors is an integer number (3419577).

Almost surely, 2^21168745 is an apocalyptic number.

It is an amenable number.

21168745 is a deficient number, since it is larger than the sum of its proper divisors (6187871).

21168745 is a wasteful number, since it uses less digits than its factorization.

21168745 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 325691.

The product of its digits is 13440, while the sum is 34.

The square root of 21168745 is about 4600.9504452885. The cubic root of 21168745 is about 276.6294227377.

The spelling of 21168745 in words is "twenty-one million, one hundred sixty-eight thousand, seven hundred forty-five".