20806380 has 144 divisors (see below), whose sum is σ = 73819200. Its totient is φ = 4741632.

The previous prime is 20806339. The next prime is 20806391. The reversal of 20806380 is 8360802.

20806380 is a `hidden beast` number, since 20 + 8 + 0 + 638 + 0 = 666.

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, 61572 + ... + 61908.

Almost surely, 2^20806380 is an apocalyptic number.

20806380 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 20806380, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (36909600).

20806380 is an abundant number, since it is smaller than the sum of its proper divisors (53012820).

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

20806380 is a wasteful number, since it uses less digits than its factorization.

20806380 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 373 (or 354 counting only the distinct ones).

The product of its (nonzero) digits is 2304, while the sum is 27.

The square root of 20806380 is about 4561.4011005392. The cubic root of 20806380 is about 275.0418889358.

The spelling of 20806380 in words is "twenty million, eight hundred six thousand, three hundred eighty".