31303220321 has 4 divisors (see below), whose sum is σ = 31433109444. Its totient is φ = 31173331200.

The previous prime is 31303220279. The next prime is 31303220341. The reversal of 31303220321 is 12302230313.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 12302230313 = 239 ⋅51473767.

It can be written as a sum of positive squares in 2 ways, for example, as 10052869696 + 21250350625 = 100264^2 + 145775^2 .

It is a cyclic number.

It is not a de Polignac number, because 31303220321 - 2³⁰ = 30229478497 is a prime.

It is a Duffinian number.

It is a Curzon number.

It is a junction number, because it is equal to n+sod(n) for n = 31303220293 and 31303220302.

It is not an unprimeable number, because it can be changed into a prime (31303220341) by changing a digit.

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 3 ways as a sum of consecutive naturals, for example, 64944200 + ... + 64944681.

It is an arithmetic number, because the mean of its divisors is an integer number (7858277361).

Almost surely, 2^31303220321 is an apocalyptic number.

It is an amenable number.

31303220321 is a deficient number, since it is larger than the sum of its proper divisors (129889123).

31303220321 is a wasteful number, since it uses less digits than its factorization.

31303220321 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 129889122.

The product of its (nonzero) digits is 648, while the sum is 20.

Adding to 31303220321 its reverse (12302230313), we get a palindrome (43605450634).

The spelling of 31303220321 in words is "thirty-one billion, three hundred three million, two hundred twenty thousand, three hundred twenty-one".