20847456 has 144 divisors (see below), whose sum is σ = 70447104. Its totient is φ = 5940864.

The previous prime is 20847451. The next prime is 20847481. The reversal of 20847456 is 65474802.

It is a tau number, because it is divible by the number of its divisors (144).

It is a Harshad number since it is a multiple of its sum of digits (36).

It is a self number, because there is not a number n which added to its sum of digits gives 20847456.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (20847451) by changing a digit.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 54241 + ... + 54623.

It is an arithmetic number, because the mean of its divisors is an integer number (489216).

Almost surely, 2^20847456 is an apocalyptic number.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 20847456, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (35223552).

20847456 is an abundant number, since it is smaller than the sum of its proper divisors (49599648).

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

20847456 is an equidigital number, since it uses as much as digits as its factorization.

20847456 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 415 (or 395 counting only the distinct ones).

The product of its (nonzero) digits is 53760, while the sum is 36.

The square root of 20847456 is about 4565.9014444028. The cubic root of 20847456 is about 275.2227660542. Note that the first 3 decimals are identical.

The spelling of 20847456 in words is "twenty million, eight hundred forty-seven thousand, four hundred fifty-six".