21011001121201 has 24 divisors (see below), whose sum is σ = 26324591602344. Its totient is φ = 16622119745280.

The previous prime is 21011001121181. The next prime is 21011001121213. The reversal of 21011001121201 is 10212110011012.

It is a happy number.

It can be written as a sum of positive squares in 4 ways, for example, as 6852751186176 + 14158249935025 = 2617776^2 + 3762745^2 .

It is not a de Polignac number, because 21011001121201 - 2²⁷ = 21010866903473 is a prime.

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

It is not an unprimeable number, because it can be changed into a prime (21011001121001) 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, 3440461 + ... + 7338853.

It is an arithmetic number, because the mean of its divisors is an integer number (1096857983431).

Almost surely, 2^{21011001121201} is an apocalyptic number.

It is an amenable number.

21011001121201 is a deficient number, since it is larger than the sum of its proper divisors (5313590481143).

21011001121201 is a wasteful number, since it uses less digits than its factorization.

21011001121201 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 3906881 (or 3906874 counting only the distinct ones).

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

Adding to 21011001121201 its reverse (10212110011012), we get a palindrome (31223111132213).

The spelling of 21011001121201 in words is "twenty-one trillion, eleven billion, one million, one hundred twenty-one thousand, two hundred one".