39965861 has 16 divisors (see below), whose sum is σ = 45856944. Its totient is φ = 34504704.

The previous prime is 39965803. The next prime is 39965897. The reversal of 39965861 is 16856993.

It can be written as a sum of positive squares in 8 ways, for example, as 7873636 + 32092225 = 2806^2 + 5665^2 .

It is not a de Polignac number, because 39965861 - 2¹⁸ = 39703717 is a prime.

It is a Duffinian number.

It is a Curzon number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (39965561) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 42185 + ... + 43121.

It is an arithmetic number, because the mean of its divisors is an integer number (2866059).

Almost surely, 2^39965861 is an apocalyptic number.

It is an amenable number.

39965861 is a deficient number, since it is larger than the sum of its proper divisors (5891083).

39965861 is a wasteful number, since it uses less digits than its factorization.

39965861 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1160.

The product of its digits is 349920, while the sum is 47.

The square root of 39965861 is about 6321.8558192986. The cubic root of 39965861 is about 341.8978668612.

The spelling of 39965861 in words is "thirty-nine million, nine hundred sixty-five thousand, eight hundred sixty-one".