21020112 has 60 divisors (see below), whose sum is σ = 59816484. Its totient is φ = 6888960.

The previous prime is 21020093. The next prime is 21020117. The reversal of 21020112 is 21102012.

It can be written as a sum of positive squares in 2 ways, for example, as 553536 + 20466576 = 744^2 + 4524^2 .

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 = 21020094 and 21020103.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21020117) 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 11 ways as a sum of consecutive naturals, for example, 7588 + ... + 9980.

Almost surely, 2^21020112 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 21020112, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (29908242).

21020112 is an abundant number, since it is smaller than the sum of its proper divisors (38796372).

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

21020112 is a wasteful number, since it uses less digits than its factorization.

21020112 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2468 (or 2459 counting only the distinct ones).

The product of its (nonzero) digits is 8, while the sum is 9.

The square root of 21020112 is about 4584.7695689097. The cubic root of 21020112 is about 275.9804649059.

Adding to 21020112 its reverse (21102012), we get a palindrome (42122124).

The spelling of 21020112 in words is "twenty-one million, twenty thousand, one hundred twelve".