21100032 has 120 divisors (see below), whose sum is σ = 64367160. Its totient is φ = 6635520.

The previous prime is 21100021. The next prime is 21100033. The reversal of 21100032 is 23000112.

It is a happy number.

It is a super-2 number, since 2×21100032² = 890422700802048, which contains 22 as substring.

It is a Harshad number since it is a multiple of its sum of digits (9).

It is a junction number, because it is equal to n+sod(n) for n = 21099987 and 21100023.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21100033) 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, 87432 + ... + 87672.

It is an arithmetic number, because the mean of its divisors is an integer number (536393).

Almost surely, 2^21100032 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 21100032, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (32183580).

21100032 is an abundant number, since it is smaller than the sum of its proper divisors (43267128).

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

21100032 is a wasteful number, since it uses less digits than its factorization.

21100032 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 284 (or 265 counting only the distinct ones).

The product of its (nonzero) digits is 12, while the sum is 9.

The square root of 21100032 is about 4593.4771143438. The cubic root of 21100032 is about 276.3297885181.

Adding to 21100032 its reverse (23000112), we get a palindrome (44100144).

The spelling of 21100032 in words is "twenty-one million, one hundred thousand, thirty-two".