39961645 has 16 divisors (see below), whose sum is σ = 51021360. Its totient is φ = 29942784.

The previous prime is 39961639. The next prime is 39961661. The reversal of 39961645 is 54616993.

It can be written as a sum of positive squares in 8 ways, for example, as 4571044 + 35390601 = 2138^2 + 5949^2 .

It is a cyclic number.

It is not a de Polignac number, because 39961645 - 2³ = 39961637 is a prime.

It is a super-3 number, since 3×39961645³ (a number of 24 digits) contains 333 as substring. Note that it is a super-d number also for d = 2.

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 18439 + ... + 20491.

It is an arithmetic number, because the mean of its divisors is an integer number (3188835).

Almost surely, 2^39961645 is an apocalyptic number.

It is an amenable number.

39961645 is a deficient number, since it is larger than the sum of its proper divisors (11059715).

39961645 is a wasteful number, since it uses less digits than its factorization.

39961645 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2304.

The product of its digits is 174960, while the sum is 43.

The square root of 39961645 is about 6321.5223641145. The cubic root of 39961645 is about 341.8858441660.

The spelling of 39961645 in words is "thirty-nine million, nine hundred sixty-one thousand, six hundred forty-five".