661107217 has 8 divisors (see below), whose sum is σ = 679084416. Its totient is φ = 643293072.

The previous prime is 661107211. The next prime is 661107233. The reversal of 661107217 is 712701166.

661107217 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

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

It is a cyclic number.

It is not a de Polignac number, because 661107217 - 2¹⁹ = 660582929 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (661107211) 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, 32523 + ... + 48784.

It is an arithmetic number, because the mean of its divisors is an integer number (84885552).

Almost surely, 2^661107217 is an apocalyptic number.

661107217 is the 16262-nd heptagonal number.

It is an amenable number.

661107217 is a deficient number, since it is larger than the sum of its proper divisors (17977199).

661107217 is a wasteful number, since it uses less digits than its factorization.

661107217 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 81527.

The product of its (nonzero) digits is 3528, while the sum is 31.

The square root of 661107217 is about 25712.0053088047. The cubic root of 661107217 is about 871.1453699347.

The spelling of 661107217 in words is "six hundred sixty-one million, one hundred seven thousand, two hundred seventeen".