39688209961 has 27 divisors (see below), whose sum is σ = 42019695237. Its totient is φ = 37485047040.

The previous prime is 39688209941. The next prime is 39688209971. The reversal of 39688209961 is 16990288693.

The square root of 39688209961 is 199219.

It is a perfect power (a square), and thus also a powerful number.

It can be written as a sum of positive squares in 4 ways, for example, as 34907317225 + 4780892736 = 186835^2 + 69144^2 .

It is not a de Polignac number, because 39688209961 - 2³⁵ = 5328471593 is a prime.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 39688209961.

It is not an unprimeable number, because it can be changed into a prime (39688209901) by changing a digit.

It is a polite number, since it can be written in 26 ways as a sum of consecutive naturals, for example, 351223041 + ... + 351223153.

Almost surely, 2^39688209961 is an apocalyptic number.

39688209961 is the 199219-th square number.

39688209961 is the 99610-th centered octagonal number.

It is an amenable number.

39688209961 is a deficient number, since it is larger than the sum of its proper divisors (2331485276).

39688209961 is an frugal number, since it uses more digits than its factorization.

39688209961 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 394 (or 197 counting only the distinct ones).

The product of its (nonzero) digits is 10077696, while the sum is 61.

The spelling of 39688209961 in words is "thirty-nine billion, six hundred eighty-eight million, two hundred nine thousand, nine hundred sixty-one".