1766398985 has 24 divisors (see below), whose sum is σ = 2301978840. Its totient is φ = 1301164800.

The previous prime is 1766398969. The next prime is 1766398987. The reversal of 1766398985 is 5898936671.

It is a happy number.

It can be written as a sum of positive squares in 12 ways, for example, as 832668736 + 933730249 = 28856^2 + 30557^2 .

It is not a de Polignac number, because 1766398985 - 2⁴ = 1766398969 is a prime.

It is a Curzon number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1766398987) by changing a digit.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 4404785 + ... + 4405185.

It is an arithmetic number, because the mean of its divisors is an integer number (95915785).

Almost surely, 2^1766398985 is an apocalyptic number.

It is an amenable number.

1766398985 is a deficient number, since it is larger than the sum of its proper divisors (535579855).

1766398985 is an frugal number, since it uses more digits than its factorization.

1766398985 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 846 (or 419 counting only the distinct ones).

The product of its digits is 19595520, while the sum is 62.

The square root of 1766398985 is about 42028.5496418803. The cubic root of 1766398985 is about 1208.8236147657.

The spelling of 1766398985 in words is "one billion, seven hundred sixty-six million, three hundred ninety-eight thousand, nine hundred eighty-five".