191012551 has 2 divisors, whose sum is σ = 191012552. Its totient is φ = 191012550.

The previous prime is 191012543. The next prime is 191012557. The reversal of 191012551 is 155210191.

It is a happy number.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 191012551 - 2³ = 191012543 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (191012557) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 95506275 + 95506276.

It is an arithmetic number, because the mean of its divisors is an integer number (95506276).

Almost surely, 2^191012551 is an apocalyptic number.

191012551 is a deficient number, since it is larger than the sum of its proper divisors (1).

191012551 is an equidigital number, since it uses as much as digits as its factorization.

191012551 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 450, while the sum is 25.

The square root of 191012551 is about 13820.7290328694. The cubic root of 191012551 is about 575.9091362184.

The spelling of 191012551 in words is "one hundred ninety-one million, twelve thousand, five hundred fifty-one".