191112821 has 2 divisors, whose sum is σ = 191112822. Its totient is φ = 191112820.

The previous prime is 191112781. The next prime is 191112829. The reversal of 191112821 is 128211191.

191112821 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 190826596 + 286225 = 13814^2 + 535^2 .

It is a cyclic number.

It is not a de Polignac number, because 191112821 - 2¹⁸ = 190850677 is a prime.

It is a super-2 number, since 2×191112821² = 73048220701156082, which contains 22 as substring.

It is a Chen prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (191112829) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 95556410 + 95556411.

It is an arithmetic number, because the mean of its divisors is an integer number (95556411).

Almost surely, 2^191112821 is an apocalyptic number.

It is an amenable number.

191112821 is a deficient number, since it is larger than the sum of its proper divisors (1).

191112821 is an equidigital number, since it uses as much as digits as its factorization.

191112821 is an evil number, because the sum of its binary digits is even.

The product of its digits is 288, while the sum is 26.

The square root of 191112821 is about 13824.3560790367. The cubic root of 191112821 is about 576.0098910419.

The spelling of 191112821 in words is "one hundred ninety-one million, one hundred twelve thousand, eight hundred twenty-one".