2191894531 has 2 divisors, whose sum is σ = 2191894532. Its totient is φ = 2191894530.

The previous prime is 2191894519. The next prime is 2191894543. The reversal of 2191894531 is 1354981912.

It is a balanced prime because it is at equal distance from previous prime (2191894519) and next prime (2191894543).

It is a cyclic number.

It is not a de Polignac number, because 2191894531 - 2²³ = 2183505923 is a prime.

It is a super-2 number, since 2×2191894531² = 9608803270055419922, which contains 22 as substring.

It is not a weakly prime, because it can be changed into another prime (2191894571) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 1095947265 + 1095947266.

It is an arithmetic number, because the mean of its divisors is an integer number (1095947266).

Almost surely, 2^2191894531 is an apocalyptic number.

2191894531 is the 20938-th centered decagonal number.

2191894531 is a deficient number, since it is larger than the sum of its proper divisors (1).

2191894531 is an equidigital number, since it uses as much as digits as its factorization.

2191894531 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 77760, while the sum is 43.

The square root of 2191894531 is about 46817.6732762319. The cubic root of 2191894531 is about 1298.9922231021.

The spelling of 2191894531 in words is "two billion, one hundred ninety-one million, eight hundred ninety-four thousand, five hundred thirty-one".