21868263 has 12 divisors (see below), whose sum is σ = 31703568. Its totient is φ = 14525280.

The previous prime is 21868247. The next prime is 21868289. The reversal of 21868263 is 36286812.

It is not a de Polignac number, because 21868263 - 2⁴ = 21868247 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21860263) by changing a digit.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 1795 + ... + 6852.

It is an arithmetic number, because the mean of its divisors is an integer number (2641964).

Almost surely, 2^21868263 is an apocalyptic number.

21868263 is a deficient number, since it is larger than the sum of its proper divisors (9835305).

21868263 is a wasteful number, since it uses less digits than its factorization.

21868263 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 8934 (or 8931 counting only the distinct ones).

The product of its digits is 27648, while the sum is 36.

The square root of 21868263 is about 4676.3514624117. The cubic root of 21868263 is about 279.6435216871.

The spelling of 21868263 in words is "twenty-one million, eight hundred sixty-eight thousand, two hundred sixty-three".