21144432 has 20 divisors (see below), whose sum is σ = 54623240. Its totient is φ = 7048128.

The previous prime is 21144419. The next prime is 21144437. The reversal of 21144432 is 23444112.

It is a nude number because it is divisible by every one of its digits.

It is a junction number, because it is equal to n+sod(n) for n = 21144399 and 21144408.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21144437) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 220207 + ... + 220302.

It is an arithmetic number, because the mean of its divisors is an integer number (2731162).

Almost surely, 2^21144432 is an apocalyptic number.

It is an amenable number.

21144432 is an abundant number, since it is smaller than the sum of its proper divisors (33478808).

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

21144432 is a wasteful number, since it uses less digits than its factorization.

21144432 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 440520 (or 440514 counting only the distinct ones).

The product of its digits is 768, while the sum is 21.

The square root of 21144432 is about 4598.3075147276. The cubic root of 21144432 is about 276.5234761690.

Adding to 21144432 its reverse (23444112), we get a palindrome (44588544).

It can be divided in two parts, 21 and 144432, that added together give a triangular number (144453 = T₅₃₇).

The spelling of 21144432 in words is "twenty-one million, one hundred forty-four thousand, four hundred thirty-two".