20807440 has 40 divisors (see below), whose sum is σ = 48657600. Its totient is φ = 8274816.

The previous prime is 20807407. The next prime is 20807443. The reversal of 20807440 is 4470802.

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

It is not an unprimeable number, because it can be changed into a prime (20807443) 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, 15267 + ... + 16573.

It is an arithmetic number, because the mean of its divisors is an integer number (1216440).

Almost surely, 2^20807440 is an apocalyptic number.

20807440 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

20807440 is an abundant number, since it is smaller than the sum of its proper divisors (27850160).

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

20807440 is a wasteful number, since it uses less digits than its factorization.

20807440 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1519 (or 1513 counting only the distinct ones).

The product of its (nonzero) digits is 1792, while the sum is 25.

The square root of 20807440 is about 4561.5172914284. The cubic root of 20807440 is about 275.0465596098.

The spelling of 20807440 in words is "twenty million, eight hundred seven thousand, four hundred forty".