1661677358785 has 8 divisors (see below), whose sum is σ = 2021328075240. Its totient is φ = 1311131723904.

The previous prime is 1661677358707. The next prime is 1661677358791. The reversal of 1661677358785 is 5878537761661.

It can be written as a sum of positive squares in 4 ways, for example, as 100354636944 + 1561322721841 = 316788^2 + 1249529^2 .

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 1661677358785 - 2¹⁹ = 1661676834497 is a prime.

It is a super-2 number, since 2×1661677358785² (a number of 25 digits) contains 22 as substring.

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 2276269990 + ... + 2276270719.

It is an arithmetic number, because the mean of its divisors is an integer number (252666009405).

Almost surely, 2^{1661677358785} is an apocalyptic number.

It is an amenable number.

1661677358785 is a deficient number, since it is larger than the sum of its proper divisors (359650716455).

1661677358785 is an equidigital number, since it uses as much as digits as its factorization.

1661677358785 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 4552540787.

The product of its digits is 355622400, while the sum is 70.

The spelling of 1661677358785 in words is "one trillion, six hundred sixty-one billion, six hundred seventy-seven million, three hundred fifty-eight thousand, seven hundred eighty-five".