221071271921 has 4 divisors (see below), whose sum is σ = 221887033344. Its totient is φ = 220255510500.

The previous prime is 221071271893. The next prime is 221071271923. The reversal of 221071271921 is 129172170122.

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 a de Polignac number, because none of the positive numbers 2^k-221071271921 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (221071271923) 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, 407880305 + ... + 407880846.

It is an arithmetic number, because the mean of its divisors is an integer number (55471758336).

Almost surely, 2^221071271921 is an apocalyptic number.

It is an amenable number.

221071271921 is a deficient number, since it is larger than the sum of its proper divisors (815761423).

221071271921 is an equidigital number, since it uses as much as digits as its factorization.

221071271921 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 815761422.

The product of its (nonzero) digits is 7056, while the sum is 35.

The spelling of 221071271921 in words is "two hundred twenty-one billion, seventy-one million, two hundred seventy-one thousand, nine hundred twenty-one".