8188221981 has 8 divisors (see below), whose sum is σ = 11171527840. Its totient is φ = 5331865392.

The previous prime is 8188221919. The next prime is 8188222001. The reversal of 8188221981 is 1891228818.

It is a sphenic number, since it is the product of 3 distinct primes.

It is not a de Polignac number, because 8188221981 - 2¹⁷ = 8188090909 is a prime.

It is a super-2 number, since 2×8188221981² (a number of 21 digits) contains 22 as substring.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 8188221981.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (8188228981) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 31737166 + ... + 31737423.

It is an arithmetic number, because the mean of its divisors is an integer number (1396440980).

Almost surely, 2^8188221981 is an apocalyptic number.

It is an amenable number.

8188221981 is a deficient number, since it is larger than the sum of its proper divisors (2983305859).

8188221981 is a wasteful number, since it uses less digits than its factorization.

8188221981 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 63474635.

The product of its digits is 147456, while the sum is 48.

The square root of 8188221981 is about 90488.7947814535. The cubic root of 8188221981 is about 2015.5637359777.

The spelling of 8188221981 in words is "eight billion, one hundred eighty-eight million, two hundred twenty-one thousand, nine hundred eighty-one".