21011220202201 has 4 divisors (see below), whose sum is σ = 21012913438900. Its totient is φ = 21009526965504.

The previous prime is 21011220202183. The next prime is 21011220202229. The reversal of 21011220202201 is 10220202211012.

It is a happy number.

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 1036220166601 + 19975000035600 = 1017949^2 + 4469340^2 .

It is a cyclic number.

It is not a de Polignac number, because 21011220202201 - 2⁷ = 21011220202073 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (21011220202001) 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, 846599736 + ... + 846624553.

It is an arithmetic number, because the mean of its divisors is an integer number (5253228359725).

Almost surely, 2^{21011220202201} is an apocalyptic number.

It is an amenable number.

21011220202201 is a deficient number, since it is larger than the sum of its proper divisors (1693236699).

21011220202201 is a wasteful number, since it uses less digits than its factorization.

21011220202201 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1693236698.

The product of its (nonzero) digits is 64, while the sum is 16.

Adding to 21011220202201 its reverse (10220202211012), we get a palindrome (31231422413213).

The spelling of 21011220202201 in words is "twenty-one trillion, eleven billion, two hundred twenty million, two hundred two thousand, two hundred one".