20806740 has 96 divisors (see below), whose sum is σ = 66044160. Its totient is φ = 5436288.

The previous prime is 20806733. The next prime is 20806741. The reversal of 20806740 is 4760802.

It is a Harshad number since it is a multiple of its sum of digits (27).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (20806741) by changing a digit.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 28257 + ... + 28983.

It is an arithmetic number, because the mean of its divisors is an integer number (687960).

Almost surely, 2^20806740 is an apocalyptic number.

20806740 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 20806740, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (33022080).

20806740 is an abundant number, since it is smaller than the sum of its proper divisors (45237420).

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

20806740 is a wasteful number, since it uses less digits than its factorization.

20806740 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 798 (or 790 counting only the distinct ones).

The product of its (nonzero) digits is 2688, while the sum is 27.

The square root of 20806740 is about 4561.4405619278. The cubic root of 20806740 is about 275.0434752202.

The spelling of 20806740 in words is "twenty million, eight hundred six thousand, seven hundred forty".