20806660 has 48 divisors (see below), whose sum is σ = 50198400. Its totient is φ = 7096320.

The previous prime is 20806637. The next prime is 20806661. The reversal of 20806660 is 6660802.

It is a happy number.

It is a Harshad number since it is a multiple of its sum of digits (28).

It is not an unprimeable number, because it can be changed into a prime (20806661) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 46116 + ... + 46564.

It is an arithmetic number, because the mean of its divisors is an integer number (1045800).

Almost surely, 2^20806660 is an apocalyptic number.

20806660 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 20806660, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (25099200).

20806660 is an abundant number, since it is smaller than the sum of its proper divisors (29391740).

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

20806660 is a wasteful number, since it uses less digits than its factorization.

20806660 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 796 (or 794 counting only the distinct ones).

The product of its (nonzero) digits is 3456, while the sum is 28.

The square root of 20806660 is about 4561.4317927598. The cubic root of 20806660 is about 275.0431227142.

The spelling of 20806660 in words is "twenty million, eight hundred six thousand, six hundred sixty".