321320402666 has 4 divisors (see below), whose sum is σ = 481980604002. Its totient is φ = 160660201332.

The previous prime is 321320402653. The next prime is 321320402677. The reversal of 321320402666 is 666204023123.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 666204023123 = 151 ⋅4411947173.

It can be written as a sum of positive squares in only one way, i.e., 282886760641 + 38433642025 = 531871^2 + 196045^2 .

It is an unprimeable number.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 80330100665 + ... + 80330100668.

Almost surely, 2^321320402666 is an apocalyptic number.

321320402666 is a deficient number, since it is larger than the sum of its proper divisors (160660201336).

321320402666 is a wasteful number, since it uses less digits than its factorization.

321320402666 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 160660201335.

The product of its (nonzero) digits is 62208, while the sum is 35.

Adding to 321320402666 its reverse (666204023123), we get a palindrome (987524425789).

The spelling of 321320402666 in words is "three hundred twenty-one billion, three hundred twenty million, four hundred two thousand, six hundred sixty-six".