21793765 has 16 divisors (see below), whose sum is σ = 31189248. Its totient is φ = 14294016.

The previous prime is 21793763. The next prime is 21793769. The reversal of 21793765 is 56739712.

It is a cyclic number.

It is not a de Polignac number, because 21793765 - 2¹ = 21793763 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21793763) 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 15 ways as a sum of consecutive naturals, for example, 12732 + ... + 14341.

It is an arithmetic number, because the mean of its divisors is an integer number (1949328).

Almost surely, 2^21793765 is an apocalyptic number.

It is an amenable number.

21793765 is a deficient number, since it is larger than the sum of its proper divisors (9395483).

21793765 is a wasteful number, since it uses less digits than its factorization.

21793765 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 27108.

The product of its digits is 79380, while the sum is 40.

The square root of 21793765 is about 4668.3792690826. The cubic root of 21793765 is about 279.3256091504.

The spelling of 21793765 in words is "twenty-one million, seven hundred ninety-three thousand, seven hundred sixty-five".