21011232 has 96 divisors (see below), whose sum is σ = 61072704. Its totient is φ = 6272000.

The previous prime is 21011231. The next prime is 21011233. The reversal of 21011232 is 23211012.

It is an interprime number because it is at equal distance from previous prime (21011231) and next prime (21011233).

It is a tau number, because it is divible by the number of its divisors (96).

It is a Harshad number since it is a multiple of its sum of digits (12).

It is not an unprimeable number, because it can be changed into a prime (21011231) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 106558 + ... + 106754.

It is an arithmetic number, because the mean of its divisors is an integer number (636174).

Almost surely, 2^21011232 is an apocalyptic number.

21011232 is a gapful number since it is divisible by the number (22) formed by its first and last digit.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 21011232, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (30536352).

21011232 is an abundant number, since it is smaller than the sum of its proper divisors (40061472).

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

21011232 is a wasteful number, since it uses less digits than its factorization.

21011232 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 322 (or 314 counting only the distinct ones).

The product of its (nonzero) digits is 24, while the sum is 12.

The square root of 21011232 is about 4583.8010428028. The cubic root of 21011232 is about 275.9415965480.

Adding to 21011232 its reverse (23211012), we get a palindrome (44222244).

It can be divided in two parts, 2101 and 1232, that added together give a palindrome (3333).

The spelling of 21011232 in words is "twenty-one million, eleven thousand, two hundred thirty-two".