21518080 has 36 divisors (see below), whose sum is σ = 51545592. Its totient is φ = 8606720.

The previous prime is 21518059. The next prime is 21518083. The reversal of 21518080 is 8081512.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21518083) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 7126 + ... + 9685.

It is an arithmetic number, because the mean of its divisors is an integer number (1431822).

Almost surely, 2^21518080 is an apocalyptic number.

21518080 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

21518080 is an abundant number, since it is smaller than the sum of its proper divisors (30027512).

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

21518080 is an equidigital number, since it uses as much as digits as its factorization.

21518080 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 16832 (or 16818 counting only the distinct ones).

The product of its (nonzero) digits is 640, while the sum is 25.

The square root of 21518080 is about 4638.7584545867. The cubic root of 21518080 is about 278.1428108781.

Adding to 21518080 its reverse (8081512), we get a palindrome (29599592).

The spelling of 21518080 in words is "twenty-one million, five hundred eighteen thousand, eighty".