20865180 has 144 divisors (see below), whose sum is σ = 69866496. Its totient is φ = 4636800.

The previous prime is 20865179. The next prime is 20865193. The reversal of 20865180 is 8156802.

It is a Harshad number since it is a multiple of its sum of digits (30).

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 47 ways as a sum of consecutive naturals, for example, 138105 + ... + 138255.

It is an arithmetic number, because the mean of its divisors is an integer number (485184).

Almost surely, 2^20865180 is an apocalyptic number.

20865180 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 20865180, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (34933248).

20865180 is an abundant number, since it is smaller than the sum of its proper divisors (49001316).

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

20865180 is a wasteful number, since it uses less digits than its factorization.

20865180 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 224 (or 215 counting only the distinct ones).

The product of its (nonzero) digits is 3840, while the sum is 30.

The square root of 20865180 is about 4567.8419412234. The cubic root of 20865180 is about 275.3007398617.

The spelling of 20865180 in words is "twenty million, eight hundred sixty-five thousand, one hundred eighty".