21111111202120 has 16 divisors (see below), whose sum is σ = 47500000204860. Its totient is φ = 8444444480832.

The previous prime is 21111111202099. The next prime is 21111111202127. The reversal of 21111111202120 is 2120211111112.

It can be written as a sum of positive squares in 2 ways, for example, as 17499279369796 + 3611831832324 = 4183214^2 + 1900482^2 .

It is a junction number, because it is equal to n+sod(n) for n = 21111111202094 and 21111111202103.

It is not an unprimeable number, because it can be changed into a prime (21111111202127) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 263888889987 + ... + 263888890066.

Almost surely, 2^{21111111202120} is an apocalyptic number.

21111111202120 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

21111111202120 is an abundant number, since it is smaller than the sum of its proper divisors (26388889002740).

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

21111111202120 is a wasteful number, since it uses less digits than its factorization.

21111111202120 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 527777780064 (or 527777780060 counting only the distinct ones).

The product of its (nonzero) digits is 16, while the sum is 16.

Adding to 21111111202120 its reverse (2120211111112), we get a palindrome (23231322313232).

The spelling of 21111111202120 in words is "twenty-one trillion, one hundred eleven billion, one hundred eleven million, two hundred two thousand, one hundred twenty".