1661873187249 has 80 divisors (see below), whose sum is σ = 2742150438720. Its totient is φ = 994612608000.

The previous prime is 1661873187223. The next prime is 1661873187259. The reversal of 1661873187249 is 9427813781661.

1661873187249 is a `hidden beast` number, since 1 + 6 + 618 + 7 + 3 + 1 + 8 + 7 + 2 + 4 + 9 = 666.

It is not a de Polignac number, because 1661873187249 - 2¹¹ = 1661873185201 is a prime.

It is not an unprimeable number, because it can be changed into a prime (1661873187259) by changing a digit.

It is a polite number, since it can be written in 79 ways as a sum of consecutive naturals, for example, 64298569 + ... + 64324409.

It is an arithmetic number, because the mean of its divisors is an integer number (34276880484).

Almost surely, 2^{1661873187249} is an apocalyptic number.

It is an amenable number.

1661873187249 is a deficient number, since it is larger than the sum of its proper divisors (1080277251471).

1661873187249 is a wasteful number, since it uses less digits than its factorization.

1661873187249 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 26764 (or 26755 counting only the distinct ones).

The product of its digits is 24385536, while the sum is 63.

The spelling of 1661873187249 in words is "one trillion, six hundred sixty-one billion, eight hundred seventy-three million, one hundred eighty-seven thousand, two hundred forty-nine".