19917384541 has 2 divisors, whose sum is σ = 19917384542. Its totient is φ = 19917384540.

The previous prime is 19917384503. The next prime is 19917384583. The reversal of 19917384541 is 14548371991.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 19706263641 + 211120900 = 140379^2 + 14530^2 .

It is a cyclic number.

It is not a de Polignac number, because 19917384541 - 2¹¹ = 19917382493 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (19917384041) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 9958692270 + 9958692271.

It is an arithmetic number, because the mean of its divisors is an integer number (9958692271).

Almost surely, 2^19917384541 is an apocalyptic number.

It is an amenable number.

19917384541 is a deficient number, since it is larger than the sum of its proper divisors (1).

19917384541 is an equidigital number, since it uses as much as digits as its factorization.

19917384541 is an evil number, because the sum of its binary digits is even.

The product of its digits is 1088640, while the sum is 52.

The spelling of 19917384541 in words is "nineteen billion, nine hundred seventeen million, three hundred eighty-four thousand, five hundred forty-one".