21100992 has 112 divisors (see below), whose sum is σ = 62130432. Its totient is φ = 6266880.

The previous prime is 21100969. The next prime is 21100993. The reversal of 21100992 is 29900112.

It is a Harshad number since it is a multiple of its sum of digits (24).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21100993) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 204813 + ... + 204915.

It is an arithmetic number, because the mean of its divisors is an integer number (554736).

Almost surely, 2^21100992 is an apocalyptic number.

21100992 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 21100992, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (31065216).

21100992 is an abundant number, since it is smaller than the sum of its proper divisors (41029440).

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

21100992 is a wasteful number, since it uses less digits than its factorization.

21100992 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 226 (or 216 counting only the distinct ones).

The product of its (nonzero) digits is 324, while the sum is 24.

The square root of 21100992 is about 4593.5816091586. The cubic root of 21100992 is about 276.3339792317. Note that the first 3 decimals are identical.

The spelling of 21100992 in words is "twenty-one million, one hundred thousand, nine hundred ninety-two".