21001012121011 has 16 divisors (see below), whose sum is σ = 23396690923200. Its totient is φ = 18716812103808.

The previous prime is 21001012120939. The next prime is 21001012121017. The reversal of 21001012121011 is 11012121010012.

It is a happy number.

It is not a de Polignac number, because 21001012121011 - 2²¹ = 21001010023859 is a prime.

It is a Harshad number since it is a multiple of its sum of digits (13).

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 21001012120982 and 21001012121000.

It is not an unprimeable number, because it can be changed into a prime (21001012121017) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 28483665 + ... + 29211661.

It is an arithmetic number, because the mean of its divisors is an integer number (1462293182700).

Almost surely, 2^{21001012121011} is an apocalyptic number.

21001012121011 is a deficient number, since it is larger than the sum of its proper divisors (2395678802189).

21001012121011 is a wasteful number, since it uses less digits than its factorization.

21001012121011 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 804558.

The product of its (nonzero) digits is 8, while the sum is 13.

Adding to 21001012121011 its reverse (11012121010012), we get a palindrome (32013133131023).

The spelling of 21001012121011 in words is "twenty-one trillion, one billion, twelve million, one hundred twenty-one thousand, eleven".