21001102120 has 32 divisors (see below), whose sum is σ = 48257856000. Its totient is φ = 8221707328.

The previous prime is 21001102091. The next prime is 21001102121. The reversal of 21001102120 is 2120110012.

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

It is a junction number, because it is equal to n+sod(n) for n = 21001102097 and 21001102106.

It is not an unprimeable number, because it can be changed into a prime (21001102121) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 5583520 + ... + 5587279.

It is an arithmetic number, because the mean of its divisors is an integer number (1508058000).

Almost surely, 2^21001102120 is an apocalyptic number.

21001102120 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

21001102120 is an abundant number, since it is smaller than the sum of its proper divisors (27256753880).

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

21001102120 is a wasteful number, since it uses less digits than its factorization.

21001102120 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 11170857 (or 11170853 counting only the distinct ones).

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

Adding to 21001102120 its reverse (2120110012), we get a palindrome (23121212132).

The spelling of 21001102120 in words is "twenty-one billion, one million, one hundred two thousand, one hundred twenty".