18871379209 has 2 divisors, whose sum is σ = 18871379210. Its totient is φ = 18871379208.

The previous prime is 18871379179. The next prime is 18871379287. The reversal of 18871379209 is 90297317881.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 10450563984 + 8420815225 = 102228^2 + 91765^2 .

It is a cyclic number.

It is not a de Polignac number, because 18871379209 - 2²⁷ = 18737161481 is a prime.

It is a super-2 number, since 2×18871379209² (a number of 21 digits) contains 22 as substring.

It is a self number, because there is not a number n which added to its sum of digits gives 18871379209.

It is not a weakly prime, because it can be changed into another prime (18871079209) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 9435689604 + 9435689605.

It is an arithmetic number, because the mean of its divisors is an integer number (9435689605).

Almost surely, 2^18871379209 is an apocalyptic number.

It is an amenable number.

18871379209 is a deficient number, since it is larger than the sum of its proper divisors (1).

18871379209 is an equidigital number, since it uses as much as digits as its factorization.

18871379209 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 1524096, while the sum is 55.

The spelling of 18871379209 in words is "eighteen billion, eight hundred seventy-one million, three hundred seventy-nine thousand, two hundred nine".