21111480 has 144 divisors (see below), whose sum is σ = 74510280. Its totient is φ = 5181696.

The previous prime is 21111479. The next prime is 21111481. The reversal of 21111480 is 8411112.

It is an interprime number because it is at equal distance from previous prime (21111479) and next prime (21111481).

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

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21111481) by changing a digit.

It is a polite number, since it can be written in 35 ways as a sum of consecutive naturals, for example, 60667 + ... + 61013.

Almost surely, 2^21111480 is an apocalyptic number.

21111480 is a gapful number since it is divisible by the number (20) 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 21111480, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (37255140).

21111480 is an abundant number, since it is smaller than the sum of its proper divisors (53398800).

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

21111480 is a wasteful number, since it uses less digits than its factorization.

21111480 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 390 (or 370 counting only the distinct ones).

The product of its (nonzero) digits is 64, while the sum is 18.

The square root of 21111480 is about 4594.7230602072. The cubic root of 21111480 is about 276.3797545004.

Adding to 21111480 its reverse (8411112), we get a palindrome (29522592).

The spelling of 21111480 in words is "twenty-one million, one hundred eleven thousand, four hundred eighty".