21011121100 has 72 divisors (see below), whose sum is σ = 49833560448. Its totient is φ = 7654886400.

The previous prime is 21011121073. The next prime is 21011121127. The reversal of 21011121100 is 112111012.

It is an interprime number because it is at equal distance from previous prime (21011121073) and next prime (21011121127).

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 23 ways as a sum of consecutive naturals, for example, 146647 + ... + 252046.

It is an arithmetic number, because the mean of its divisors is an integer number (692132784).

Almost surely, 2^21011121100 is an apocalyptic number.

21011121100 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

21011121100 is an abundant number, since it is smaller than the sum of its proper divisors (28822439348).

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

21011121100 is a wasteful number, since it uses less digits than its factorization.

21011121100 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 398755 (or 398748 counting only the distinct ones).

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

Adding to 21011121100 its reverse (112111012), we get a palindrome (21123232112).

The spelling of 21011121100 in words is "twenty-one billion, eleven million, one hundred twenty-one thousand, one hundred".