16870778809 has 2 divisors, whose sum is σ = 16870778810. Its totient is φ = 16870778808.

The previous prime is 16870778791. The next prime is 16870778843. The reversal of 16870778809 is 90887707861.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 15963564409 + 907214400 = 126347^2 + 30120^2 .

It is a cyclic number.

It is not a de Polignac number, because 16870778809 - 2¹⁵ = 16870746041 is a prime.

It is not a weakly prime, because it can be changed into another prime (16870778009) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 8435389404 + 8435389405.

It is an arithmetic number, because the mean of its divisors is an integer number (8435389405).

Almost surely, 2^16870778809 is an apocalyptic number.

It is an amenable number.

16870778809 is a deficient number, since it is larger than the sum of its proper divisors (1).

16870778809 is an equidigital number, since it uses as much as digits as its factorization.

16870778809 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 9483264, while the sum is 61.

The spelling of 16870778809 in words is "sixteen billion, eight hundred seventy million, seven hundred seventy-eight thousand, eight hundred nine".