661155241202609 has 8 divisors (see below), whose sum is σ = 662682571690920. Its totient is φ = 659629385686656.

The previous prime is 661155241202581. The next prime is 661155241202641. The reversal of 661155241202609 is 906202142551166.

It can be written as a sum of positive squares in 4 ways, for example, as 305747081640625 + 355408159561984 = 17485625^2 + 18852272^2 .

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 661155241202609 - 2¹² = 661155241198513 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (661155241202699) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (23) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 367845554 + ... + 369638555.

It is an arithmetic number, because the mean of its divisors is an integer number (82835321461365).

Almost surely, 2^{661155241202609} is an apocalyptic number.

It is an amenable number.

661155241202609 is a deficient number, since it is larger than the sum of its proper divisors (1527330488311).

661155241202609 is a wasteful number, since it uses less digits than its factorization.

661155241202609 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 737486179.

The product of its (nonzero) digits is 1555200, while the sum is 50.

The spelling of 661155241202609 in words is "six hundred sixty-one trillion, one hundred fifty-five billion, two hundred forty-one million, two hundred two thousand, six hundred nine".