16881221671 has 4 divisors (see below), whose sum is σ = 16898679952. Its totient is φ = 16863763392.

The previous prime is 16881221653. The next prime is 16881221681. The reversal of 16881221671 is 17612218861.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 17612218861 = 151 ⋅116637211.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-16881221671 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (16881221641) 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, 8727690 + ... + 8729623.

It is an arithmetic number, because the mean of its divisors is an integer number (4224669988).

Almost surely, 2^16881221671 is an apocalyptic number.

16881221671 is a deficient number, since it is larger than the sum of its proper divisors (17458281).

16881221671 is an equidigital number, since it uses as much as digits as its factorization.

16881221671 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 17458280.

The product of its digits is 64512, while the sum is 43.

The spelling of 16881221671 in words is "sixteen billion, eight hundred eighty-one million, two hundred twenty-one thousand, six hundred seventy-one".