16778770385 has 12 divisors (see below), whose sum is σ = 21802474332. Its totient is φ = 12390475968.

The previous prime is 16778770343. The next prime is 16778770387. The reversal of 16778770385 is 58307787761.

It can be written as a sum of positive squares in 6 ways, for example, as 4270361104 + 12508409281 = 65348^2 + 111841^2 .

It is not a de Polignac number, because 16778770385 - 2⁶ = 16778770321 is a prime.

It is a Duffinian number.

It is a Curzon number.

It is not an unprimeable number, because it can be changed into a prime (16778770387) by changing a digit.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 9927422 + ... + 9929111.

It is an arithmetic number, because the mean of its divisors is an integer number (1816872861).

Almost surely, 2^16778770385 is an apocalyptic number.

It is an amenable number.

16778770385 is a deficient number, since it is larger than the sum of its proper divisors (5023703947).

16778770385 is a wasteful number, since it uses less digits than its factorization.

16778770385 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 19856564 (or 19856551 counting only the distinct ones).

The product of its (nonzero) digits is 13829760, while the sum is 59.

The spelling of 16778770385 in words is "sixteen billion, seven hundred seventy-eight million, seven hundred seventy thousand, three hundred eighty-five".