20547840 has 72 divisors (see below), whose sum is σ = 65636928. Its totient is φ = 5478400.

The previous prime is 20547827. The next prime is 20547853. The reversal of 20547840 is 4874502.

It is an interprime number because it is at equal distance from previous prime (20547827) and next prime (20547853).

It is a Harshad number since it is a multiple of its sum of digits (30).

It is a junction number, because it is equal to n+sod(n) for n = 20547798 and 20547807.

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, 1165 + ... + 6515.

It is an arithmetic number, because the mean of its divisors is an integer number (911624).

Almost surely, 2^20547840 is an apocalyptic number.

20547840 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 20547840, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (32818464).

20547840 is an abundant number, since it is smaller than the sum of its proper divisors (45089088).

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

20547840 is an equidigital number, since it uses as much as digits as its factorization.

20547840 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 5375 (or 5361 counting only the distinct ones).

The product of its (nonzero) digits is 8960, while the sum is 30.

The square root of 20547840 is about 4532.9725346620. The cubic root of 20547840 is about 273.8979142673.

The spelling of 20547840 in words is "twenty million, five hundred forty-seven thousand, eight hundred forty".