21000011121100 has 36 divisors (see below), whose sum is σ = 49712753602008. Its totient is φ = 7636367680000.

The previous prime is 21000011121049. The next prime is 21000011121121. The reversal of 21000011121100 is 112111000012.

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

It is an unprimeable number.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 9545458501 + ... + 9545460700.

It is an arithmetic number, because the mean of its divisors is an integer number (1380909822278).

Almost surely, 2^{21000011121100} is an apocalyptic number.

21000011121100 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

21000011121100 is an abundant number, since it is smaller than the sum of its proper divisors (28712742480908).

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

21000011121100 is a wasteful number, since it uses less digits than its factorization.

21000011121100 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 19090919226 (or 19090919219 counting only the distinct ones).

The product of its (nonzero) digits is 4, while the sum is 10.

Adding to 21000011121100 its reverse (112111000012), we get a palindrome (21112122121112).

The spelling of 21000011121100 in words is "twenty-one trillion, eleven million, one hundred twenty-one thousand, one hundred".