21101002120 has 32 divisors (see below), whose sum is σ = 51793369920. Its totient is φ = 7673091520.

The previous prime is 21101002099. The next prime is 21101002129. The reversal of 21101002120 is 2120010112.

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 = 21101002097 and 21101002106.

It is not an unprimeable number, because it can be changed into a prime (21101002129) 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, 23977972 + ... + 23978851.

It is an arithmetic number, because the mean of its divisors is an integer number (1618542810).

Almost surely, 2^21101002120 is an apocalyptic number.

21101002120 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

21101002120 is an abundant number, since it is smaller than the sum of its proper divisors (30692367800).

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

21101002120 is a wasteful number, since it uses less digits than its factorization.

21101002120 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 47956845 (or 47956841 counting only the distinct ones).

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

Adding to 21101002120 its reverse (2120010112), we get a palindrome (23221012232).

The spelling of 21101002120 in words is "twenty-one billion, one hundred one million, two thousand, one hundred twenty".