1681617601645 has 8 divisors (see below), whose sum is σ = 2043484680960. Its totient is φ = 1328265042000.

The previous prime is 1681617601627. The next prime is 1681617601669. The reversal of 1681617601645 is 5461067161861.

It is a happy number.

It is a sphenic number, since it is the product of 3 distinct primes.

It is not a de Polignac number, because 1681617601645 - 2¹⁵ = 1681617568877 is a prime.

It is a super-3 number, since 3×1681617601645³ (a number of 38 digits) contains 333 as substring.

It is a junction number, because it is equal to n+sod(n) for n = 1681617601592 and 1681617601601.

It is a congruent number.

It is an unprimeable number.

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 7 ways as a sum of consecutive naturals, for example, 2128629481 + ... + 2128630270.

It is an arithmetic number, because the mean of its divisors is an integer number (255435585120).

Almost surely, 2^{1681617601645} is an apocalyptic number.

It is an amenable number.

1681617601645 is a deficient number, since it is larger than the sum of its proper divisors (361867079315).

1681617601645 is an equidigital number, since it uses as much as digits as its factorization.

1681617601645 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 4257259835.

The product of its (nonzero) digits is 1451520, while the sum is 52.

The spelling of 1681617601645 in words is "one trillion, six hundred eighty-one billion, six hundred seventeen million, six hundred one thousand, six hundred forty-five".