20207840 has 48 divisors (see below), whose sum is σ = 48662208. Its totient is φ = 7927296.

The previous prime is 20207839. The next prime is 20207843. The reversal of 20207840 is 4870202.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (20207843) 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, 7289 + ... + 9671.

It is an arithmetic number, because the mean of its divisors is an integer number (1013796).

Almost surely, 2^20207840 is an apocalyptic number.

20207840 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 20207840, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (24331104).

20207840 is an abundant number, since it is smaller than the sum of its proper divisors (28454368).

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

20207840 is a wasteful number, since it uses less digits than its factorization.

20207840 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2451 (or 2443 counting only the distinct ones).

The product of its (nonzero) digits is 896, while the sum is 23.

The square root of 20207840 is about 4495.3131147897. The cubic root of 20207840 is about 272.3787974869.

The spelling of 20207840 in words is "twenty million, two hundred seven thousand, eight hundred forty".