221212111001 has 4 divisors (see below), whose sum is σ = 252813841152. Its totient is φ = 189610380852.

The previous prime is 221212110997. The next prime is 221212111007. The reversal of 221212111001 is 100111212122.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4, and also an emirpimes, since its reverse is a distinct semiprime: 100111212122 = 2 ⋅50055606061.

It is a cyclic number.

It is not a de Polignac number, because 221212111001 - 2² = 221212110997 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (221212111007) 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, 15800865065 + ... + 15800865078.

It is an arithmetic number, because the mean of its divisors is an integer number (63203460288).

Almost surely, 2^221212111001 is an apocalyptic number.

It is an amenable number.

221212111001 is a deficient number, since it is larger than the sum of its proper divisors (31601730151).

221212111001 is an equidigital number, since it uses as much as digits as its factorization.

221212111001 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 31601730150.

The product of its (nonzero) digits is 16, while the sum is 14.

Adding to 221212111001 its reverse (100111212122), we get a palindrome (321323323123).

The spelling of 221212111001 in words is "two hundred twenty-one billion, two hundred twelve million, one hundred eleven thousand, one".