21875663 has 4 divisors (see below), whose sum is σ = 21895368. Its totient is φ = 21855960.

The previous prime is 21875647. The next prime is 21875699. The reversal of 21875663 is 36657812.

It is a semiprime because it is the product of two primes.

It is a cyclic number.

It is not a de Polignac number, because 21875663 - 2⁴ = 21875647 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 (21875603) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 8081 + ... + 10442.

It is an arithmetic number, because the mean of its divisors is an integer number (5473842).

Almost surely, 2^21875663 is an apocalyptic number.

21875663 is a deficient number, since it is larger than the sum of its proper divisors (19705).

21875663 is a wasteful number, since it uses less digits than its factorization.

21875663 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 19704.

The product of its digits is 60480, while the sum is 38.

The square root of 21875663 is about 4677.1426106117. The cubic root of 21875663 is about 279.6750609804.

The spelling of 21875663 in words is "twenty-one million, eight hundred seventy-five thousand, six hundred sixty-three".