20644255100 has 72 divisors (see below), whose sum is σ = 51380440608. Its totient is φ = 7052774400.

The previous prime is 20644255057. The next prime is 20644255109. The reversal of 20644255100 is 155244602.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (20644255109) 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, 144224 + ... + 249176.

Almost surely, 2^20644255100 is an apocalyptic number.

20644255100 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 20644255100, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (25690220304).

20644255100 is an abundant number, since it is smaller than the sum of its proper divisors (30736185508).

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

20644255100 is a wasteful number, since it uses less digits than its factorization.

20644255100 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 105255 (or 105248 counting only the distinct ones).

The product of its (nonzero) digits is 9600, while the sum is 29.

Adding to 20644255100 its reverse (155244602), we get a palindrome (20799499702).

The spelling of 20644255100 in words is "twenty billion, six hundred forty-four million, two hundred fifty-five thousand, one hundred".