21111992 has 64 divisors (see below), whose sum is σ = 45619200. Its totient is φ = 9072000.

The previous prime is 21111991. The next prime is 21112009. The reversal of 21111992 is 29911112.

It is a hoax number, since the sum of its digits (26) coincides with the sum of the digits of its distinct prime factors.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21111991) 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, 193634 + ... + 193742.

It is an arithmetic number, because the mean of its divisors is an integer number (712800).

Almost surely, 2^21111992 is an apocalyptic number.

21111992 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 21111992, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (22809600).

21111992 is an abundant number, since it is smaller than the sum of its proper divisors (24507208).

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

21111992 is a wasteful number, since it uses less digits than its factorization.

21111992 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 228 (or 224 counting only the distinct ones).

The product of its digits is 324, while the sum is 26.

The square root of 21111992 is about 4594.7787759586. The cubic root of 21111992 is about 276.3819887554.

The spelling of 21111992 in words is "twenty-one million, one hundred eleven thousand, nine hundred ninety-two".