21863826 has 12 divisors (see below), whose sum is σ = 47371662. Its totient is φ = 7287936.

The previous prime is 21863801. The next prime is 21863827. The reversal of 21863826 is 62836812.

21863826 is a `hidden beast` number, since 2 + 18 + 638 + 2 + 6 = 666.

It can be written as a sum of positive squares in only one way, i.e., 14814801 + 7049025 = 3849^2 + 2655^2 .

It is not an unprimeable number, because it can be changed into a prime (21863827) 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 5 ways as a sum of consecutive naturals, for example, 607311 + ... + 607346.

Almost surely, 2^21863826 is an apocalyptic number.

21863826 is an abundant number, since it is smaller than the sum of its proper divisors (25507836).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

21863826 is a wasteful number, since it uses less digits than its factorization.

21863826 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1214665 (or 1214662 counting only the distinct ones).

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

The square root of 21863826 is about 4675.8770300340. The cubic root of 21863826 is about 279.6246074851.

The spelling of 21863826 in words is "twenty-one million, eight hundred sixty-three thousand, eight hundred twenty-six".