19800381647 has 2 divisors, whose sum is σ = 19800381648. Its totient is φ = 19800381646.

The previous prime is 19800381641. The next prime is 19800381691. The reversal of 19800381647 is 74618300891.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 19800381647 - 2¹² = 19800377551 is a prime.

It is a super-2 number, since 2×19800381647² (a number of 21 digits) contains 22 as substring.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (19800381641) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 9900190823 + 9900190824.

It is an arithmetic number, because the mean of its divisors is an integer number (9900190824).

Almost surely, 2^19800381647 is an apocalyptic number.

19800381647 is a deficient number, since it is larger than the sum of its proper divisors (1).

19800381647 is an equidigital number, since it uses as much as digits as its factorization.

19800381647 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 290304, while the sum is 47.

The spelling of 19800381647 in words is "nineteen billion, eight hundred million, three hundred eighty-one thousand, six hundred forty-seven".