1661738361737 has 4 divisors (see below), whose sum is σ = 1661910590100. Its totient is φ = 1661566133376.

The previous prime is 1661738361719. The next prime is 1661738361769. The reversal of 1661738361737 is 7371638371661.

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 929043449161 + 732694912576 = 963869^2 + 855976^2 .

It is a cyclic number.

It is not a de Polignac number, because 1661738361737 - 2³⁴ = 1644558492553 is a prime.

It is a super-2 number, since 2×1661738361737² (a number of 25 digits) contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (1661738361637) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 86099708 + ... + 86119005.

It is an arithmetic number, because the mean of its divisors is an integer number (415477647525).

Almost surely, 2^{1661738361737} is an apocalyptic number.

It is an amenable number.

1661738361737 is a deficient number, since it is larger than the sum of its proper divisors (172228363).

1661738361737 is an equidigital number, since it uses as much as digits as its factorization.

1661738361737 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 172228362.

The product of its digits is 16003008, while the sum is 59.

The spelling of 1661738361737 in words is "one trillion, six hundred sixty-one billion, seven hundred thirty-eight million, three hundred sixty-one thousand, seven hundred thirty-seven".