21131112 has 32 divisors (see below), whose sum is σ = 55126080. Its totient is φ = 6737280.

The previous prime is 21131087. The next prime is 21131137. The reversal of 21131112 is 21113112.

It is an interprime number because it is at equal distance from previous prime (21131087) and next prime (21131137).

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

It is a nude number because it is divisible by every one of its digits and also a Zuckerman number because it is divisible by the product of its digits.

It is a zygodrome in base 13.

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 18589 + ... + 19692.

It is an arithmetic number, because the mean of its divisors is an integer number (1722690).

Almost surely, 2^21131112 is an apocalyptic number.

It is an amenable number.

21131112 is an abundant number, since it is smaller than the sum of its proper divisors (33994968).

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

21131112 is a wasteful number, since it uses less digits than its factorization.

21131112 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 38313 (or 38309 counting only the distinct ones).

The product of its digits is 12, while the sum is 12.

The square root of 21131112 is about 4596.8589275722. The cubic root of 21131112 is about 276.4653983670.

Adding to 21131112 its reverse (21113112), we get a palindrome (42244224).

The spelling of 21131112 in words is "twenty-one million, one hundred thirty-one thousand, one hundred twelve".