21012011120105 has 4 divisors (see below), whose sum is σ = 25214413344132. Its totient is φ = 16809608896080.

The previous prime is 21012011120069. The next prime is 21012011120129. The reversal of 21012011120105 is 50102111021012.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 11856369982864 + 9155641137241 = 3443308^2 + 3025829^2 .

It is not a de Polignac number, because 21012011120105 - 2¹⁰ = 21012011119081 is a prime.

It is a super-2 number, since 2×21012011120105² (a number of 27 digits) contains 22 as substring.

It is a Duffinian number.

It is an unprimeable number.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 2101201112006 + ... + 2101201112015.

It is an arithmetic number, because the mean of its divisors is an integer number (6303603336033).

Almost surely, 2^{21012011120105} is an apocalyptic number.

It is an amenable number.

21012011120105 is a deficient number, since it is larger than the sum of its proper divisors (4202402224027).

21012011120105 is an equidigital number, since it uses as much as digits as its factorization.

21012011120105 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 4202402224026.

The product of its (nonzero) digits is 40, while the sum is 17.

Adding to 21012011120105 its reverse (50102111021012), we get a palindrome (71114122141117).

The spelling of 21012011120105 in words is "twenty-one trillion, twelve billion, eleven million, one hundred twenty thousand, one hundred five".