19850891 has 2 divisors, whose sum is σ = 19850892. Its totient is φ = 19850890.

The previous prime is 19850869. The next prime is 19850893. The reversal of 19850891 is 19805891.

It is a strong prime.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-19850891 is a prime.

Together with 19850893, it forms a pair of twin primes.

It is a Chen prime.

It is not a weakly prime, because it can be changed into another prime (19850893) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 9925445 + 9925446.

It is an arithmetic number, because the mean of its divisors is an integer number (9925446).

Almost surely, 2^19850891 is an apocalyptic number.

19850891 is a deficient number, since it is larger than the sum of its proper divisors (1).

19850891 is an equidigital number, since it uses as much as digits as its factorization.

19850891 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 25920, while the sum is 41.

The square root of 19850891 is about 4455.4338733731. The cubic root of 19850891 is about 270.7655047709.

The spelling of 19850891 in words is "nineteen million, eight hundred fifty thousand, eight hundred ninety-one".