21155112 has 48 divisors (see below), whose sum is σ = 62506080. Its totient is φ = 6410400.

The previous prime is 21155107. The next prime is 21155117.

21155112 is nontrivially palindromic in base 10.

It is an interprime number because it is at equal distance from previous prime (21155107) and next prime (21155117).

It is a Harshad number since it is a multiple of its sum of digits (18).

It is not an unprimeable number, because it can be changed into a prime (21155117) 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, 12564 + ... + 14147.

It is an arithmetic number, because the mean of its divisors is an integer number (1302210).

Almost surely, 2^21155112 is an apocalyptic number.

21155112 is a gapful number since it is divisible by the number (22) formed by its first and last digit.

It is an amenable number.

21155112 is an abundant number, since it is smaller than the sum of its proper divisors (41350968).

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

21155112 is a wasteful number, since it uses less digits than its factorization.

21155112 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 26734 (or 26727 counting only the distinct ones).

The product of its digits is 100, while the sum is 18.

The square root of 21155112 is about 4599.4686649656. The cubic root of 21155112 is about 276.5700254392.

It can be divided in two parts, 2115 and 5112, that added together give a palindrome (7227).

The spelling of 21155112 in words is "twenty-one million, one hundred fifty-five thousand, one hundred twelve".