19957877309 has 2 divisors, whose sum is σ = 19957877310. Its totient is φ = 19957877308.

The previous prime is 19957877263. The next prime is 19957877327. The reversal of 19957877309 is 90377875991.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 19662209284 + 295668025 = 140222^2 + 17195^2 .

It is a cyclic number.

It is not a de Polignac number, because 19957877309 - 2³² = 15662910013 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (19957877339) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 9978938654 + 9978938655.

It is an arithmetic number, because the mean of its divisors is an integer number (9978938655).

Almost surely, 2^19957877309 is an apocalyptic number.

It is an amenable number.

19957877309 is a deficient number, since it is larger than the sum of its proper divisors (1).

19957877309 is an equidigital number, since it uses as much as digits as its factorization.

19957877309 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 30005640, while the sum is 65.

The spelling of 19957877309 in words is "nineteen billion, nine hundred fifty-seven million, eight hundred seventy-seven thousand, three hundred nine".