18912971843 has 2 divisors, whose sum is σ = 18912971844. Its totient is φ = 18912971842.

The previous prime is 18912971839. The next prime is 18912971893. The reversal of 18912971843 is 34817921981.

It is a weak prime.

It is an emirp because it is prime and its reverse (34817921981) is a distict prime.

It is a cyclic number.

It is not a de Polignac number, because 18912971843 - 2² = 18912971839 is a prime.

It is a super-2 number, since 2×18912971843² (a number of 21 digits) contains 22 as substring.

It is not a weakly prime, because it can be changed into another prime (18912971813) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 9456485921 + 9456485922.

It is an arithmetic number, because the mean of its divisors is an integer number (9456485922).

Almost surely, 2^18912971843 is an apocalyptic number.

18912971843 is a deficient number, since it is larger than the sum of its proper divisors (1).

18912971843 is an equidigital number, since it uses as much as digits as its factorization.

18912971843 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 870912, while the sum is 53.

The spelling of 18912971843 in words is "eighteen billion, nine hundred twelve million, nine hundred seventy-one thousand, eight hundred forty-three".