661131243 has 12 divisors (see below), whose sum is σ = 957241168. Its totient is φ = 439704720.

The previous prime is 661131223. The next prime is 661131257. The reversal of 661131243 is 342131166.

661131243 is a `hidden beast` number, since 6 + 611 + 3 + 1 + 2 + 43 = 666.

It is not a de Polignac number, because 661131243 - 2¹⁰ = 661130219 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (661131223) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 83455 + ... + 91032.

Almost surely, 2^661131243 is an apocalyptic number.

661131243 is a deficient number, since it is larger than the sum of its proper divisors (296109925).

661131243 is a wasteful number, since it uses less digits than its factorization.

661131243 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 174914 (or 174911 counting only the distinct ones).

The product of its digits is 2592, while the sum is 27.

The square root of 661131243 is about 25712.4725182157. The cubic root of 661131243 is about 871.1559228801.

The spelling of 661131243 in words is "six hundred sixty-one million, one hundred thirty-one thousand, two hundred forty-three".