19810254209 has 2 divisors, whose sum is σ = 19810254210. Its totient is φ = 19810254208.

The previous prime is 19810254161. The next prime is 19810254307. The reversal of 19810254209 is 90245201891.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 18539545600 + 1270708609 = 136160^2 + 35647^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-19810254209 is a prime.

It is not a weakly prime, because it can be changed into another prime (19810254509) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 9905127104 + 9905127105.

It is an arithmetic number, because the mean of its divisors is an integer number (9905127105).

Almost surely, 2^19810254209 is an apocalyptic number.

It is an amenable number.

19810254209 is a deficient number, since it is larger than the sum of its proper divisors (1).

19810254209 is an equidigital number, since it uses as much as digits as its factorization.

19810254209 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 51840, while the sum is 41.

The spelling of 19810254209 in words is "nineteen billion, eight hundred ten million, two hundred fifty-four thousand, two hundred nine".