18971873 has 2 divisors, whose sum is σ = 18971874. Its totient is φ = 18971872.

The previous prime is 18971867. The next prime is 18971893. The reversal of 18971873 is 37817981.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 18861649 + 110224 = 4343^2 + 332^2 .

It is an emirp because it is prime and its reverse (37817981) is a distict prime.

It is a cyclic number.

It is not a de Polignac number, because 18971873 - 2⁴ = 18971857 is a prime.

It is not a weakly prime, because it can be changed into another prime (18971833) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 9485936 + 9485937.

It is an arithmetic number, because the mean of its divisors is an integer number (9485937).

Almost surely, 2^18971873 is an apocalyptic number.

It is an amenable number.

18971873 is a deficient number, since it is larger than the sum of its proper divisors (1).

18971873 is an equidigital number, since it uses as much as digits as its factorization.

18971873 is an evil number, because the sum of its binary digits is even.

The product of its digits is 84672, while the sum is 44.

The square root of 18971873 is about 4355.6713604219. The cubic root of 18971873 is about 266.7084259256.

The spelling of 18971873 in words is "eighteen million, nine hundred seventy-one thousand, eight hundred seventy-three".