21100101010101 has 24 divisors (see below), whose sum is σ = 31301920745784. Its totient is φ = 13686434213760.

The previous prime is 21100101010081. The next prime is 21100101010169. The reversal of 21100101010101 is 10101010100112.

It can be written as a sum of positive squares in 4 ways, for example, as 12356813831076 + 8743287179025 = 3515226^2 + 2956905^2 .

It is not a de Polignac number, because 21100101010101 - 2¹¹ = 21100101008053 is a prime.

It is a Harshad number since it is a multiple of its sum of digits (9).

21100101010101 is a modest number, since divided by 1010101 gives 211001 as remainder.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21100101020101) by changing a digit.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 55708975 + ... + 56086451.

It is an arithmetic number, because the mean of its divisors is an integer number (1304246697741).

Almost surely, 2^{21100101010101} is an apocalyptic number.

It is an amenable number.

21100101010101 is a deficient number, since it is larger than the sum of its proper divisors (10201819735683).

21100101010101 is a wasteful number, since it uses less digits than its factorization.

21100101010101 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 545381 (or 545378 counting only the distinct ones).

The product of its (nonzero) digits is 2, while the sum is 9.

Adding to 21100101010101 its reverse (10101010100112), we get a palindrome (31201111110213).

The spelling of 21100101010101 in words is "twenty-one trillion, one hundred billion, one hundred one million, ten thousand, one hundred one".