221001002001 has 24 divisors (see below), whose sum is σ = 345506907200. Its totient is φ = 135317182176.

The previous prime is 221001001993. The next prime is 221001002009. The reversal of 221001002001 is 100200100122.

It is an interprime number because it is at equal distance from previous prime (221001001993) and next prime (221001002009).

It is not a de Polignac number, because 221001002001 - 2³ = 221001001993 is a prime.

It is a Harshad number since it is a multiple of its sum of digits (9).

It is not an unprimeable number, because it can be changed into a prime (221001002009) 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, 4722691 + ... + 4769256.

Almost surely, 2^221001002001 is an apocalyptic number.

It is an amenable number.

221001002001 is a deficient number, since it is larger than the sum of its proper divisors (124505905199).

221001002001 is a wasteful number, since it uses less digits than its factorization.

221001002001 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 9492165 (or 9492162 counting only the distinct ones).

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

Adding to 221001002001 its reverse (100200100122), we get a palindrome (321201102123).

The spelling of 221001002001 in words is "two hundred twenty-one billion, one million, two thousand, one".