20121210100 has 18 divisors (see below), whose sum is σ = 43663026134. Its totient is φ = 8048484000.

The previous prime is 20121210089. The next prime is 20121210113. The reversal of 20121210100 is 101212102.

It can be written as a sum of positive squares in 3 ways, for example, as 577729296 + 19543480804 = 24036^2 + 139798^2 .

It is a Harshad number since it is a multiple of its sum of digits (10).

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 100605951 + ... + 100606150.

Almost surely, 2^20121210100 is an apocalyptic number.

20121210100 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

20121210100 is an abundant number, since it is smaller than the sum of its proper divisors (23541816034).

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

20121210100 is a wasteful number, since it uses less digits than its factorization.

20121210100 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 201212115 (or 201212108 counting only the distinct ones).

The product of its (nonzero) digits is 8, while the sum is 10.

Adding to 20121210100 its reverse (101212102), we get a palindrome (20222422202).

The spelling of 20121210100 in words is "twenty billion, one hundred twenty-one million, two hundred ten thousand, one hundred".