1661806174594 has 4 divisors (see below), whose sum is σ = 2492709261894. Its totient is φ = 830903087296.

The previous prime is 1661806174577. The next prime is 1661806174619. The reversal of 1661806174594 is 4954716081661.

It is a happy number.

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

It can be written as a sum of positive squares in only one way, i.e., 919322368969 + 742483805625 = 958813^2 + 861675^2 .

It is a super-2 number, since 2×1661806174594² (a number of 25 digits) contains 22 as substring.

It is a Smith number, since the sum of its digits (58) coincides with the sum of the digits of its prime factors. Since it is squarefree, it is also a hoax number.

It is an unprimeable number.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 415451543647 + ... + 415451543650.

Almost surely, 2^{1661806174594} is an apocalyptic number.

1661806174594 is a deficient number, since it is larger than the sum of its proper divisors (830903087300).

1661806174594 is an equidigital number, since it uses as much as digits as its factorization.

1661806174594 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 830903087299.

The product of its (nonzero) digits is 8709120, while the sum is 58.

The spelling of 1661806174594 in words is "one trillion, six hundred sixty-one billion, eight hundred six million, one hundred seventy-four thousand, five hundred ninety-four".