20820456 has 64 divisors (see below), whose sum is σ = 59270400. Its totient is φ = 6768000.

The previous prime is 20820431. The next prime is 20820469. The reversal of 20820456 is 65402802.

20820456 is a `hidden beast` number, since 208 + 2 + 0 + 456 = 666.

It is a Harshad number since it is a multiple of its sum of digits (27).

It is an unprimeable number.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 7681 + ... + 10031.

It is an arithmetic number, because the mean of its divisors is an integer number (926100).

Almost surely, 2^20820456 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 20820456, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (29635200).

20820456 is an abundant number, since it is smaller than the sum of its proper divisors (38449944).

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

20820456 is a wasteful number, since it uses less digits than its factorization.

20820456 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2407 (or 2397 counting only the distinct ones).

The product of its (nonzero) digits is 3840, while the sum is 27.

The square root of 20820456 is about 4562.9437866360. The cubic root of 20820456 is about 275.1038990325.

The spelling of 20820456 in words is "twenty million, eight hundred twenty thousand, four hundred fifty-six".