39666561 has 8 divisors (see below), whose sum is σ = 57696864. Its totient is φ = 24040320.

The previous prime is 39666551. The next prime is 39666563. The reversal of 39666561 is 16566693.

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

It is not a de Polignac number, because 39666561 - 2¹⁰ = 39665537 is a prime.

It is not an unprimeable number, because it can be changed into a prime (39666563) by changing a digit.

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 7 ways as a sum of consecutive naturals, for example, 600976 + ... + 601041.

It is an arithmetic number, because the mean of its divisors is an integer number (7212108).

Almost surely, 2^39666561 is an apocalyptic number.

It is an amenable number.

39666561 is a deficient number, since it is larger than the sum of its proper divisors (18030303).

39666561 is a wasteful number, since it uses less digits than its factorization.

39666561 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1202031.

The product of its digits is 174960, while the sum is 42.

The square root of 39666561 is about 6298.1394871819. The cubic root of 39666561 is about 341.0422487306.

The spelling of 39666561 in words is "thirty-nine million, six hundred sixty-six thousand, five hundred sixty-one".