1965811985 has 8 divisors (see below), whose sum is σ = 2382331176. Its totient is φ = 1557078400.

The previous prime is 1965811921. The next prime is 1965811987. The reversal of 1965811985 is 5891185691.

It is a happy number.

It can be written as a sum of positive squares in 4 ways, for example, as 801569344 + 1164242641 = 28312^2 + 34121^2 .

It is a sphenic number, since it is the product of 3 distinct primes.

It is not a de Polignac number, because 1965811985 - 2⁶ = 1965811921 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (1965811987) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 1945844 + ... + 1946853.

It is an arithmetic number, because the mean of its divisors is an integer number (297791397).

Almost surely, 2^1965811985 is an apocalyptic number.

It is an amenable number.

1965811985 is a deficient number, since it is larger than the sum of its proper divisors (416519191).

1965811985 is a wasteful number, since it uses less digits than its factorization.

1965811985 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 3892803.

The product of its digits is 777600, while the sum is 53.

The square root of 1965811985 is about 44337.4783337979. The cubic root of 1965811985 is about 1252.7007174976.

The spelling of 1965811985 in words is "one billion, nine hundred sixty-five million, eight hundred eleven thousand, nine hundred eighty-five".