191420981 has 2 divisors, whose sum is σ = 191420982. Its totient is φ = 191420980.

The previous prime is 191420963. The next prime is 191421011. The reversal of 191420981 is 189024191.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 189502756 + 1918225 = 13766^2 + 1385^2 .

It is a cyclic number.

It is not a de Polignac number, because 191420981 - 2¹⁰ = 191419957 is a prime.

It is a super-2 number, since 2×191420981² = 73283983934004722, which contains 22 as substring.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (191426981) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 95710490 + 95710491.

It is an arithmetic number, because the mean of its divisors is an integer number (95710491).

Almost surely, 2^191420981 is an apocalyptic number.

It is an amenable number.

191420981 is a deficient number, since it is larger than the sum of its proper divisors (1).

191420981 is an equidigital number, since it uses as much as digits as its factorization.

191420981 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 5184, while the sum is 35.

The square root of 191420981 is about 13835.4971359905. The cubic root of 191420981 is about 576.3193206368.

The spelling of 191420981 in words is "one hundred ninety-one million, four hundred twenty thousand, nine hundred eighty-one".