1661039889617 has 16 divisors (see below), whose sum is σ = 1819669017600. Its totient is φ = 1509196012800.

The previous prime is 1661039889589. The next prime is 1661039889637. The reversal of 1661039889617 is 7169889301661.

It is a cyclic number.

It is not a de Polignac number, because 1661039889617 - 2²⁴ = 1661023112401 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (1661039889637) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 3061742 + ... + 3563192.

It is an arithmetic number, because the mean of its divisors is an integer number (113729313600).

Almost surely, 2^{1661039889617} is an apocalyptic number.

1661039889617 is a gapful number since it is divisible by the number (17) formed by its first and last digit.

It is an amenable number.

1661039889617 is a deficient number, since it is larger than the sum of its proper divisors (158629127983).

1661039889617 is a wasteful number, since it uses less digits than its factorization.

1661039889617 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 508216.

The product of its (nonzero) digits is 23514624, while the sum is 65.

The spelling of 1661039889617 in words is "one trillion, six hundred sixty-one billion, thirty-nine million, eight hundred eighty-nine thousand, six hundred seventeen".