21867444 has 36 divisors (see below), whose sum is σ = 56773444. Its totient is φ = 7091712.

The previous prime is 21867427. The next prime is 21867449. The reversal of 21867444 is 44476812.

It can be written as a sum of positive squares in 2 ways, for example, as 13046544 + 8820900 = 3612^2 + 2970^2 .

It is a tau number, because it is divible by the number of its divisors (36).

It is a Harshad number since it is a multiple of its sum of digits (36).

It is a junction number, because it is equal to n+sod(n) for n = 21867399 and 21867408.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21867449) 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, 6877 + ... + 9540.

Almost surely, 2^21867444 is an apocalyptic number.

It is an amenable number.

21867444 is an abundant number, since it is smaller than the sum of its proper divisors (34906000).

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

21867444 is a wasteful number, since it uses less digits than its factorization.

21867444 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 16464 (or 16459 counting only the distinct ones).

The product of its digits is 43008, while the sum is 36.

The square root of 21867444 is about 4676.2638933234. The cubic root of 21867444 is about 279.6400306172.

The spelling of 21867444 in words is "twenty-one million, eight hundred sixty-seven thousand, four hundred forty-four".