47187991 has 2 divisors, whose sum is σ = 47187992. Its totient is φ = 47187990.

The previous prime is 47187989. The next prime is 47187997. The reversal of 47187991 is 19978174.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 47187991 - 2¹ = 47187989 is a prime.

Together with 47187989, it forms a pair of twin primes.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (47187997) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 23593995 + 23593996.

It is an arithmetic number, because the mean of its divisors is an integer number (23593996).

Almost surely, 2^47187991 is an apocalyptic number.

47187991 is a deficient number, since it is larger than the sum of its proper divisors (1).

47187991 is an equidigital number, since it uses as much as digits as its factorization.

47187991 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 127008, while the sum is 46.

The square root of 47187991 is about 6869.3515705633. The cubic root of 47187991 is about 361.3631217036.

The spelling of 47187991 in words is "forty-seven million, one hundred eighty-seven thousand, nine hundred ninety-one".