21180432 has 120 divisors (see below), whose sum is σ = 67894464. Its totient is φ = 5571072.

The previous prime is 21180431. The next prime is 21180437. The reversal of 21180432 is 23408112.

It is a super-2 number, since 2×21180432² = 897221399413248, which contains 22 as substring.

It is a Harshad number since it is a multiple of its sum of digits (21).

It is a junction number, because it is equal to n+sod(n) for n = 21180399 and 21180408.

It is not an unprimeable number, because it can be changed into a prime (21180431) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (7) of ones.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 56598 + ... + 56970.

Almost surely, 2^21180432 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 21180432, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (33947232).

21180432 is an abundant number, since it is smaller than the sum of its proper divisors (46714032).

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

21180432 is a wasteful number, since it uses less digits than its factorization.

21180432 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 417 (or 398 counting only the distinct ones).

The product of its (nonzero) digits is 384, while the sum is 21.

The square root of 21180432 is about 4602.2203337085. The cubic root of 21180432 is about 276.6803212564.

Adding to 21180432 its reverse (23408112), we get a palindrome (44588544).

It can be divided in two parts, 21180 and 432, that added together give a palindrome (21612).

The spelling of 21180432 in words is "twenty-one million, one hundred eighty thousand, four hundred thirty-two".