191102981 has 2 divisors, whose sum is σ = 191102982. Its totient is φ = 191102980.

The previous prime is 191102971. The next prime is 191102983. The reversal of 191102981 is 189201191.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 189502756 + 1600225 = 13766^2 + 1265^2 .

It is a cyclic number.

It is not a de Polignac number, because 191102981 - 2⁶ = 191102917 is a prime.

It is a super-2 number, since 2×191102981² = 73040698694172722, which contains 22 as substring.

It is a Sophie Germain prime.

Together with 191102983, it forms a pair of twin primes.

It is a Chen prime.

It is a Curzon number.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (191102983) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 95551490 + 95551491.

It is an arithmetic number, because the mean of its divisors is an integer number (95551491).

Almost surely, 2^191102981 is an apocalyptic number.

It is an amenable number.

191102981 is a deficient number, since it is larger than the sum of its proper divisors (1).

191102981 is an equidigital number, since it uses as much as digits as its factorization.

191102981 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 1296, while the sum is 32.

The square root of 191102981 is about 13824.0001808449. Note that the first 3 decimals coincide. The cubic root of 191102981 is about 576.0000050235. Note that the first 5 decimals are identical.

The spelling of 191102981 in words is "one hundred ninety-one million, one hundred two thousand, nine hundred eighty-one".