661243314145 has 4 divisors (see below), whose sum is σ = 793491976980. Its totient is φ = 528994651312.

The previous prime is 661243314049. The next prime is 661243314157. The reversal of 661243314145 is 541413342166.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 489098814736 + 172144499409 = 699356^2 + 414903^2 .

It is a cyclic number.

It is not a de Polignac number, because 661243314145 - 2²⁵ = 661209759713 is a prime.

It is a junction number, because it is equal to n+sod(n) for n = 661243314098 and 661243314107.

It is an unprimeable number.

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 3 ways as a sum of consecutive naturals, for example, 66124331410 + ... + 66124331419.

It is an arithmetic number, because the mean of its divisors is an integer number (198372994245).

Almost surely, 2^661243314145 is an apocalyptic number.

It is an amenable number.

661243314145 is a deficient number, since it is larger than the sum of its proper divisors (132248662835).

661243314145 is a wasteful number, since it uses less digits than its factorization.

661243314145 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 132248662834.

The product of its digits is 207360, while the sum is 40.

The spelling of 661243314145 in words is "six hundred sixty-one billion, two hundred forty-three million, three hundred fourteen thousand, one hundred forty-five".