221721886673 has 4 divisors (see below), whose sum is σ = 253396441920. Its totient is φ = 190047331428.

The previous prime is 221721886643. The next prime is 221721886699. The reversal of 221721886673 is 376688127122.

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.

It is a cyclic number.

It is not a de Polignac number, because 221721886673 - 2⁸ = 221721886417 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (221721886643) 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, 15837277613 + ... + 15837277626.

It is an arithmetic number, because the mean of its divisors is an integer number (63349110480).

Almost surely, 2^221721886673 is an apocalyptic number.

It is an amenable number.

221721886673 is a deficient number, since it is larger than the sum of its proper divisors (31674555247).

221721886673 is an equidigital number, since it uses as much as digits as its factorization.

221721886673 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 31674555246.

The product of its digits is 2709504, while the sum is 53.

The spelling of 221721886673 in words is "two hundred twenty-one billion, seven hundred twenty-one million, eight hundred eighty-six thousand, six hundred seventy-three".