191077021 has 2 divisors, whose sum is σ = 191077022. Its totient is φ = 191077020.

The previous prime is 191076971. The next prime is 191077049. The reversal of 191077021 is 120770191.

It is an a-pointer prime, because the next prime (191077049) can be obtained adding 191077021 to its sum of digits (28).

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 185340996 + 5736025 = 13614^2 + 2395^2 .

It is a cyclic number.

It is not a de Polignac number, because 191077021 - 2²⁷ = 56859293 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (191078021) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 95538510 + 95538511.

It is an arithmetic number, because the mean of its divisors is an integer number (95538511).

Almost surely, 2^191077021 is an apocalyptic number.

It is an amenable number.

191077021 is a deficient number, since it is larger than the sum of its proper divisors (1).

191077021 is an equidigital number, since it uses as much as digits as its factorization.

191077021 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 882, while the sum is 28.

The square root of 191077021 is about 13823.0612022084. The cubic root of 191077021 is about 575.9739219884.

The spelling of 191077021 in words is "one hundred ninety-one million, seventy-seven thousand, twenty-one".