1320320501661 has 32 divisors (see below), whose sum is σ = 2118395151360. Its totient is φ = 714561578496.

The previous prime is 1320320501659. The next prime is 1320320501663. The reversal of 1320320501661 is 1661050230231.

It is an interprime number because it is at equal distance from previous prime (1320320501659) and next prime (1320320501663).

It is not a de Polignac number, because 1320320501661 - 2¹ = 1320320501659 is a prime.

It is a super-3 number, since 3×1320320501661³ (a number of 37 digits) contains 333 as substring.

It is a Curzon number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1320320501663) by changing a digit.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 985750 + ... + 1900616.

It is an arithmetic number, because the mean of its divisors is an integer number (66199848480).

Almost surely, 2^{1320320501661} is an apocalyptic number.

It is an amenable number.

1320320501661 is a deficient number, since it is larger than the sum of its proper divisors (798074649699).

1320320501661 is a wasteful number, since it uses less digits than its factorization.

1320320501661 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 918513.

The product of its (nonzero) digits is 6480, while the sum is 30.

Adding to 1320320501661 its reverse (1661050230231), we get a palindrome (2981370731892).

The spelling of 1320320501661 in words is "one trillion, three hundred twenty billion, three hundred twenty million, five hundred one thousand, six hundred sixty-one".