19997943 has 16 divisors (see below), whose sum is σ = 30541056. Its totient is φ = 11401920.

The previous prime is 19997911. The next prime is 19997953. The reversal of 19997943 is 34979991.

It is not a de Polignac number, because 19997943 - 2⁵ = 19997911 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (19997953) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 12763 + ... + 14243.

It is an arithmetic number, because the mean of its divisors is an integer number (1908816).

Almost surely, 2^19997943 is an apocalyptic number.

19997943 is a deficient number, since it is larger than the sum of its proper divisors (10543113).

19997943 is a wasteful number, since it uses less digits than its factorization.

19997943 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2134.

The product of its digits is 551124, while the sum is 51.

The square root of 19997943 is about 4471.9059694944. The cubic root of 19997943 is about 271.4324554120.

The spelling of 19997943 in words is "nineteen million, nine hundred ninety-seven thousand, nine hundred forty-three".