20563866400 has 576 divisors, whose sum is σ = 67428184320. Its totient is φ = 5927731200.

The previous prime is 20563866377. The next prime is 20563866403. The reversal of 20563866400 is 466836502.

It is a happy number.

It is a Harshad number since it is a multiple of its sum of digits (40).

It is not an unprimeable number, because it can be changed into a prime (20563866403) by changing a digit.

It is a polite number, since it can be written in 95 ways as a sum of consecutive naturals, for example, 76445466 + ... + 76445734.

It is an arithmetic number, because the mean of its divisors is an integer number (117062820).

Almost surely, 2^20563866400 is an apocalyptic number.

20563866400 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 20563866400, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (33714092160).

20563866400 is an abundant number, since it is smaller than the sum of its proper divisors (46864317920).

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

20563866400 is a wasteful number, since it uses less digits than its factorization.

20563866400 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 397 (or 384 counting only the distinct ones).

The product of its (nonzero) digits is 207360, while the sum is 40.

The spelling of 20563866400 in words is "twenty billion, five hundred sixty-three million, eight hundred sixty-six thousand, four hundred".