17780399449 has 2 divisors, whose sum is σ = 17780399450. Its totient is φ = 17780399448.

The previous prime is 17780399333. The next prime is 17780399513. The reversal of 17780399449 is 94499308771.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 16888302025 + 892097424 = 129955^2 + 29868^2 .

It is a cyclic number.

It is not a de Polignac number, because 17780399449 - 2¹³ = 17780391257 is a prime.

It is a super-2 number, since 2×17780399449² (a number of 21 digits) contains 22 as substring.

It is not a weakly prime, because it can be changed into another prime (17780399149) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 8890199724 + 8890199725.

It is an arithmetic number, because the mean of its divisors is an integer number (8890199725).

Almost surely, 2^17780399449 is an apocalyptic number.

It is an amenable number.

17780399449 is a deficient number, since it is larger than the sum of its proper divisors (1).

17780399449 is an equidigital number, since it uses as much as digits as its factorization.

17780399449 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 13716864, while the sum is 61.

The spelling of 17780399449 in words is "seventeen billion, seven hundred eighty million, three hundred ninety-nine thousand, four hundred forty-nine".