20643305100 has 72 divisors (see below), whose sum is σ = 65157787968. Its totient is φ = 5004436800.

The previous prime is 20643305027. The next prime is 20643305101. The reversal of 20643305100 is 150334602.

It is a happy number.

It is a super-2 number, since 2×20643305100² (a number of 21 digits) contains 22 as substring.

It is not an unprimeable number, because it can be changed into a prime (20643305101) 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, 3124474 + ... + 3131073.

Almost surely, 2^20643305100 is an apocalyptic number.

20643305100 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

20643305100 is an abundant number, since it is smaller than the sum of its proper divisors (44514482868).

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

20643305100 is a wasteful number, since it uses less digits than its factorization.

20643305100 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 6255575 (or 6255568 counting only the distinct ones).

The product of its (nonzero) digits is 2160, while the sum is 24.

Adding to 20643305100 its reverse (150334602), we get a palindrome (20793639702).

The spelling of 20643305100 in words is "twenty billion, six hundred forty-three million, three hundred five thousand, one hundred".