21863412 has 48 divisors (see below), whose sum is σ = 57294720. Its totient is φ = 7209216.

The previous prime is 21863407. The next prime is 21863423. The reversal of 21863412 is 21436812.

21863412 is a `hidden beast` number, since 2 + 18 + 634 + 12 = 666.

It is a Harshad number since it is a multiple of its sum of digits (27).

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 9433 + ... + 11519.

It is an arithmetic number, because the mean of its divisors is an integer number (1193640).

Almost surely, 2^21863412 is an apocalyptic number.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 21863412, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (28647360).

21863412 is an abundant number, since it is smaller than the sum of its proper divisors (35431308).

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

21863412 is a wasteful number, since it uses less digits than its factorization.

21863412 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2197 (or 2189 counting only the distinct ones).

The product of its digits is 2304, while the sum is 27.

The square root of 21863412 is about 4675.8327600546. The cubic root of 21863412 is about 279.6228425406.

The spelling of 21863412 in words is "twenty-one million, eight hundred sixty-three thousand, four hundred twelve".