49999991 has 2 divisors, whose sum is σ = 49999992.
Its totient is φ = 49999990.
The previous prime is 49999921. The next prime is 50000017. The reversal of 49999991 is 19999994.
It is a strong prime.
It is a cyclic number.
It is a de Polignac number, because none of the positive numbers 2k-49999991 is a prime.
It is a Chen prime.
It is a self number, because there is not a number n which added to its sum of digits gives 49999991.
It is a congruent number.
It is not a weakly prime, because it can be changed into another prime (49999921) by changing a digit.
It is a pernicious number, because its binary representation contains a prime number (17) of ones.
It is a polite number, since it can be written as a sum of consecutive naturals, namely, 24999995 + 24999996.
It is an arithmetic number, because the mean of its divisors is an integer number (24999996).
Almost surely, 249999991 is an apocalyptic number.
49999991 is a deficient number, since it is larger than the sum of its proper divisors (1).
49999991 is an equidigital number, since it uses as much as digits as its factorization.
49999991 is an odious number, because the sum of its binary digits is odd.
The product of its digits is 2125764, while the sum is 59.
The square root of 49999991 is about 7071.0671754693.
The cubic root of 49999991 is about 368.4031277598.
The spelling of 49999991 in words is "forty-nine million, nine hundred ninety-nine thousand, nine hundred ninety-one".