20855180720 has 80 divisors (see below), whose sum is σ = 52928746272. Its totient is φ = 7579054080.

The previous prime is 20855180713. The next prime is 20855180741. The reversal of 20855180720 is 2708155802.

It is a happy number.

It is a tau number, because it is divible by the number of its divisors (80).

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, 1641914 + ... + 1654566.

Almost surely, 2^20855180720 is an apocalyptic number.

20855180720 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 20855180720, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (26464373136).

20855180720 is an abundant number, since it is smaller than the sum of its proper divisors (32073565552).

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

20855180720 is a wasteful number, since it uses less digits than its factorization.

20855180720 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 14550 (or 14544 counting only the distinct ones).

The product of its (nonzero) digits is 44800, while the sum is 38.

The spelling of 20855180720 in words is "twenty billion, eight hundred fifty-five million, one hundred eighty thousand, seven hundred twenty".