21111002120 has 32 divisors (see below), whose sum is σ = 51153583320. Its totient is φ = 7794831360.

The previous prime is 21111002117. The next prime is 21111002141. The reversal of 21111002120 is 2120011112.

It can be written as a sum of positive squares in 4 ways, for example, as 16087878244 + 5023123876 = 126838^2 + 70874^2 .

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 20298521 + ... + 20299560.

Almost surely, 2^21111002120 is an apocalyptic number.

21111002120 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

21111002120 is an abundant number, since it is smaller than the sum of its proper divisors (30042581200).

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

21111002120 is a wasteful number, since it uses less digits than its factorization.

21111002120 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 40598105 (or 40598101 counting only the distinct ones).

The product of its (nonzero) digits is 8, while the sum is 11.

Adding to 21111002120 its reverse (2120011112), we get a palindrome (23231013232).

The spelling of 21111002120 in words is "twenty-one billion, one hundred eleven million, two thousand, one hundred twenty".