321155052661 has 4 divisors (see below), whose sum is σ = 321197784012. Its totient is φ = 321112321312.

The previous prime is 321155052653. The next prime is 321155052677. The reversal of 321155052661 is 166250551123.

It is a happy number.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 166250551123 = 29017 ⋅5729419.

It can be written as a sum of positive squares in 2 ways, for example, as 145099284561 + 176055768100 = 380919^2 + 419590^2 .

It is a cyclic number.

It is not a de Polignac number, because 321155052661 - 2³ = 321155052653 is a prime.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 321155052661.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (321155052641) 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, 21354400 + ... + 21369433.

It is an arithmetic number, because the mean of its divisors is an integer number (80299446003).

Almost surely, 2^321155052661 is an apocalyptic number.

It is an amenable number.

321155052661 is a deficient number, since it is larger than the sum of its proper divisors (42731351).

321155052661 is an equidigital number, since it uses as much as digits as its factorization.

321155052661 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 42731350.

The product of its (nonzero) digits is 54000, while the sum is 37.

The spelling of 321155052661 in words is "three hundred twenty-one billion, one hundred fifty-five million, fifty-two thousand, six hundred sixty-one".