20816240 has 40 divisors (see below), whose sum is σ = 48598080. Its totient is φ = 8292096.

The previous prime is 20816239. The next prime is 20816249. The reversal of 20816240 is 4261802.

It is a tau number, because it is divible by the number of its divisors (40).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (20816249) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 29006 + ... + 29714.

It is an arithmetic number, because the mean of its divisors is an integer number (1214952).

Almost surely, 2^20816240 is an apocalyptic number.

20816240 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

20816240 is an abundant number, since it is smaller than the sum of its proper divisors (27781840).

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

20816240 is a wasteful number, since it uses less digits than its factorization.

20816240 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1089 (or 1083 counting only the distinct ones).

The product of its (nonzero) digits is 768, while the sum is 23.

The square root of 20816240 is about 4562.4817807855. The cubic root of 20816240 is about 275.0853288927.

The spelling of 20816240 in words is "twenty million, eight hundred sixteen thousand, two hundred forty".