21168863 has 4 divisors (see below), whose sum is σ = 21467088. Its totient is φ = 20870640.

The previous prime is 21168827. The next prime is 21168871. The reversal of 21168863 is 36886112.

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

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-21168863 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 (21168803) 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, 149006 + ... + 149147.

It is an arithmetic number, because the mean of its divisors is an integer number (5366772).

Almost surely, 2^21168863 is an apocalyptic number.

21168863 is a deficient number, since it is larger than the sum of its proper divisors (298225).

21168863 is an equidigital number, since it uses as much as digits as its factorization.

21168863 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 298224.

The product of its digits is 13824, while the sum is 35.

The square root of 21168863 is about 4600.9632687080. The cubic root of 21168863 is about 276.6299367378.

The spelling of 21168863 in words is "twenty-one million, one hundred sixty-eight thousand, eight hundred sixty-three".