21115480 has 64 divisors (see below), whose sum is σ = 49896000. Its totient is φ = 8031744.

The previous prime is 21115453. The next prime is 21115511. The reversal of 21115480 is 8451112.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 126357 + ... + 126523.

It is an arithmetic number, because the mean of its divisors is an integer number (779625).

Almost surely, 2^21115480 is an apocalyptic number.

21115480 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 21115480, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (24948000).

21115480 is an abundant number, since it is smaller than the sum of its proper divisors (28780520).

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

21115480 is a wasteful number, since it uses less digits than its factorization.

21115480 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 316 (or 312 counting only the distinct ones).

The product of its (nonzero) digits is 320, while the sum is 22.

The square root of 21115480 is about 4595.1583215380. The cubic root of 21115480 is about 276.3972086566.

Adding to 21115480 its reverse (8451112), we get a palindrome (29566592).

The spelling of 21115480 in words is "twenty-one million, one hundred fifteen thousand, four hundred eighty".