19985263843 has 4 divisors (see below), whose sum is σ = 19995901840. Its totient is φ = 19974625848.

The previous prime is 19985263787. The next prime is 19985263847. The reversal of 19985263843 is 34836258991.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 34836258991 = 3209 ⋅10855799.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-19985263843 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (19985263847) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 5316180 + ... + 5319937.

It is an arithmetic number, because the mean of its divisors is an integer number (4998975460).

Almost surely, 2^19985263843 is an apocalyptic number.

19985263843 is a deficient number, since it is larger than the sum of its proper divisors (10637997).

19985263843 is a wasteful number, since it uses less digits than its factorization.

19985263843 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 10637996.

The product of its digits is 11197440, while the sum is 58.

The spelling of 19985263843 in words is "nineteen billion, nine hundred eighty-five million, two hundred sixty-three thousand, eight hundred forty-three".