2231818891 has 2 divisors, whose sum is σ = 2231818892. Its totient is φ = 2231818890.

The previous prime is 2231818877. The next prime is 2231818933. The reversal of 2231818891 is 1988181322.

It is a happy number.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 2231818891 - 2⁷ = 2231818763 is a prime.

It is a super-3 number, since 3×2231818891³ (a number of 29 digits) contains 333 as substring.

It is not a weakly prime, because it can be changed into another prime (2231818811) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 1115909445 + 1115909446.

It is an arithmetic number, because the mean of its divisors is an integer number (1115909446).

Almost surely, 2^2231818891 is an apocalyptic number.

2231818891 is a deficient number, since it is larger than the sum of its proper divisors (1).

2231818891 is an equidigital number, since it uses as much as digits as its factorization.

2231818891 is an evil number, because the sum of its binary digits is even.

The product of its digits is 55296, while the sum is 43.

The square root of 2231818891 is about 47242.1304663539. The cubic root of 2231818891 is about 1306.8316671827.

It can be divided in two parts, 22318 and 18891, that added together give a square (41209 = 203²).

The spelling of 2231818891 in words is "two billion, two hundred thirty-one million, eight hundred eighteen thousand, eight hundred ninety-one".