187490731991 has 2 divisors, whose sum is σ = 187490731992. Its totient is φ = 187490731990.

The previous prime is 187490731973. The next prime is 187490732029. The reversal of 187490731991 is 199137094781.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 187490731991 - 2⁶ = 187490731927 is a prime.

It is a self number, because there is not a number n which added to its sum of digits gives 187490731991.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (187490731931) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 93745365995 + 93745365996.

It is an arithmetic number, because the mean of its divisors is an integer number (93745365996).

Almost surely, 2^187490731991 is an apocalyptic number.

187490731991 is a deficient number, since it is larger than the sum of its proper divisors (1).

187490731991 is an equidigital number, since it uses as much as digits as its factorization.

187490731991 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 3429216, while the sum is 59.

The spelling of 187490731991 in words is "one hundred eighty-seven billion, four hundred ninety million, seven hundred thirty-one thousand, nine hundred ninety-one".