19850991 has 16 divisors (see below), whose sum is σ = 28391040. Its totient is φ = 12299040.

The previous prime is 19850983. The next prime is 19851017. The reversal of 19850991 is 19905891.

It is not a de Polignac number, because 19850991 - 2³ = 19850983 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (19850911) 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 in 15 ways as a sum of consecutive naturals, for example, 265 + ... + 6306.

It is an arithmetic number, because the mean of its divisors is an integer number (1774440).

Almost surely, 2^19850991 is an apocalyptic number.

19850991 is a deficient number, since it is larger than the sum of its proper divisors (8540049).

19850991 is a wasteful number, since it uses less digits than its factorization.

19850991 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 6646.

The product of its (nonzero) digits is 29160, while the sum is 42.

The square root of 19850991 is about 4455.4450956105. The cubic root of 19850991 is about 270.7659594357.

The spelling of 19850991 in words is "nineteen million, eight hundred fifty thousand, nine hundred ninety-one".