3131220321 has 20 divisors (see below), whose sum is σ = 4679180352. Its totient is φ = 2086731288.

The previous prime is 3131220271. The next prime is 3131220331. The reversal of 3131220321 is 1230221313.

3131220321 is a `hidden beast` number, since 31 + 312 + 2 + 0 + 321 = 666.

It is not a de Polignac number, because 3131220321 - 2¹³ = 3131212129 is a prime.

It is a Curzon number.

It is a junction number, because it is equal to n+sod(n) for n = 3131220294 and 3131220303.

It is not an unprimeable number, because it can be changed into a prime (3131220331) by changing a digit.

It is a polite number, since it can be written in 19 ways as a sum of consecutive naturals, for example, 307900 + ... + 317906.

Almost surely, 2^3131220321 is an apocalyptic number.

It is an amenable number.

3131220321 is a deficient number, since it is larger than the sum of its proper divisors (1547960031).

3131220321 is a wasteful number, since it uses less digits than its factorization.

3131220321 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 13882 (or 13873 counting only the distinct ones).

The product of its (nonzero) digits is 216, while the sum is 18.

The square root of 3131220321 is about 55957.3080213836. The cubic root of 3131220321 is about 1462.9782704022.

Adding to 3131220321 its reverse (1230221313), we get a palindrome (4361441634).

The spelling of 3131220321 in words is "three billion, one hundred thirty-one million, two hundred twenty thousand, three hundred twenty-one".