21743136 has 72 divisors (see below), whose sum is σ = 65483964. Its totient is φ = 6819840.

The previous prime is 21743131. The next prime is 21743177. The reversal of 21743136 is 63134712.

It can be written as a sum of positive squares in 2 ways, for example, as 21566736 + 176400 = 4644^2 + 420^2 .

It is a tau number, because it is divible by the number of its divisors (72).

It is a super-2 number, since 2×21743136² = 945527926228992, which contains 22 as substring.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21743131) 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, 2676 + ... + 7116.

Almost surely, 2^21743136 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 21743136, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (32741982).

21743136 is an abundant number, since it is smaller than the sum of its proper divisors (43740828).

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

21743136 is a wasteful number, since it uses less digits than its factorization.

21743136 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 4474 (or 4463 counting only the distinct ones).

The product of its digits is 3024, while the sum is 27.

The square root of 21743136 is about 4662.9535704315. The cubic root of 21743136 is about 279.1091414057.

Adding to 21743136 its reverse (63134712), we get a palindrome (84877848).

The spelling of 21743136 in words is "twenty-one million, seven hundred forty-three thousand, one hundred thirty-six".