20115880 has 48 divisors (see below), whose sum is σ = 46440180. Its totient is φ = 7840512.

The previous prime is 20115853. The next prime is 20115883. The reversal of 20115880 is 8851102.

It can be written as a sum of positive squares in 2 ways, for example, as 20088324 + 27556 = 4482^2 + 166^2 .

It is not an unprimeable number, because it can be changed into a prime (20115883) 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, 242319 + ... + 242401.

Almost surely, 2^20115880 is an apocalyptic number.

20115880 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 20115880, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (23220090).

20115880 is an abundant number, since it is smaller than the sum of its proper divisors (26324300).

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

20115880 is an equidigital number, since it uses as much as digits as its factorization.

20115880 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 250 (or 163 counting only the distinct ones).

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

The square root of 20115880 is about 4485.0730205873. The cubic root of 20115880 is about 271.9649969375.

Adding to 20115880 its reverse (8851102), we get a palindrome (28966982).

The spelling of 20115880 in words is "twenty million, one hundred fifteen thousand, eight hundred eighty".