221200100001 has 6 divisors (see below), whose sum is σ = 319511255570. Its totient is φ = 147466733328.

The previous prime is 221200099987. The next prime is 221200100003. The reversal of 221200100001 is 100001002122.

It can be written as a sum of positive squares in only one way, i.e., 134175690000 + 87024410001 = 366300^2 + 294999^2 .

It is not a de Polignac number, because 221200100001 - 2⁵ = 221200099969 is a prime.

It is a Harshad number since it is a multiple of its sum of digits (9), and also a Moran number because the ratio is a prime number: 24577788889 = 221200100001 / (2 + 2 + 1 + 2 + 0 + 0 + 1 + 0 + 0 + 0 + 0 + 1).

It is a Duffinian number.

It is a Curzon number.

It is not an unprimeable number, because it can be changed into a prime (221200100003) by changing a digit.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 12288894436 + ... + 12288894453.

Almost surely, 2^221200100001 is an apocalyptic number.

It is an amenable number.

221200100001 is a deficient number, since it is larger than the sum of its proper divisors (98311155569).

221200100001 is a wasteful number, since it uses less digits than its factorization.

221200100001 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 24577788895 (or 24577788892 counting only the distinct ones).

The product of its (nonzero) digits is 8, while the sum is 9.

Adding to 221200100001 its reverse (100001002122), we get a palindrome (321201102123).

It can be divided in two parts, 221200 and 100001, that added together give a triangular number (321201 = T₈₀₁).

The spelling of 221200100001 in words is "two hundred twenty-one billion, two hundred million, one hundred thousand, one".