20645108400 has 480 divisors, whose sum is σ = 78690185728. Its totient is φ = 4528742400.

The previous prime is 20645108387. The next prime is 20645108401. The reversal of 20645108400 is 480154602.

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

It is not an unprimeable number, because it can be changed into a prime (20645108401) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 95 ways as a sum of consecutive naturals, for example, 22032732 + ... + 22033668.

Almost surely, 2^20645108400 is an apocalyptic number.

20645108400 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 20645108400, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (39345092864).

20645108400 is an abundant number, since it is smaller than the sum of its proper divisors (58045077328).

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

20645108400 is a wasteful number, since it uses less digits than its factorization.

20645108400 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1069 (or 1058 counting only the distinct ones).

The product of its (nonzero) digits is 7680, while the sum is 30.

The spelling of 20645108400 in words is "twenty billion, six hundred forty-five million, one hundred eight thousand, four hundred".