20809340 has 24 divisors (see below), whose sum is σ = 43999200. Its totient is φ = 8266688.

The previous prime is 20809303. The next prime is 20809361. The reversal of 20809340 is 4390802.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 512 + ... + 6471.

It is an arithmetic number, because the mean of its divisors is an integer number (1833300).

Almost surely, 2^20809340 is an apocalyptic number.

20809340 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

20809340 is an abundant number, since it is smaller than the sum of its proper divisors (23189860).

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

20809340 is a wasteful number, since it uses less digits than its factorization.

20809340 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 7141 (or 7139 counting only the distinct ones).

The product of its (nonzero) digits is 1728, while the sum is 26.

The square root of 20809340 is about 4561.7255507100. The cubic root of 20809340 is about 275.0549311755.

The spelling of 20809340 in words is "twenty million, eight hundred nine thousand, three hundred forty".