191631920287 has 2 divisors, whose sum is σ = 191631920288. Its totient is φ = 191631920286.

The previous prime is 191631920251. The next prime is 191631920309. The reversal of 191631920287 is 782029136191.

It is a happy number.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 191631920287 - 2¹⁵ = 191631887519 is a prime.

It is a self number, because there is not a number n which added to its sum of digits gives 191631920287.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (191631920087) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 95815960143 + 95815960144.

It is an arithmetic number, because the mean of its divisors is an integer number (95815960144).

Almost surely, 2^191631920287 is an apocalyptic number.

191631920287 is a deficient number, since it is larger than the sum of its proper divisors (1).

191631920287 is an equidigital number, since it uses as much as digits as its factorization.

191631920287 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 326592, while the sum is 49.

The spelling of 191631920287 in words is "one hundred ninety-one billion, six hundred thirty-one million, nine hundred twenty thousand, two hundred eighty-seven".