19999397 has 16 divisors (see below), whose sum is σ = 22972032. Its totient is φ = 17233920.

The previous prime is 19999387. The next prime is 19999411. The reversal of 19999397 is 79399991.

It is a happy number.

It is not a de Polignac number, because 19999397 - 2⁶ = 19999333 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (19999307) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 34373 + ... + 34949.

It is an arithmetic number, because the mean of its divisors is an integer number (1435752).

Almost surely, 2^19999397 is an apocalyptic number.

It is an amenable number.

19999397 is a deficient number, since it is larger than the sum of its proper divisors (2972635).

19999397 is a wasteful number, since it uses less digits than its factorization.

19999397 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 748.

The product of its digits is 1240029, while the sum is 56.

The square root of 19999397 is about 4472.0685370419. The cubic root of 19999397 is about 271.4390336424.

The spelling of 19999397 in words is "nineteen million, nine hundred ninety-nine thousand, three hundred ninety-seven".