3121312021 has 8 divisors (see below), whose sum is σ = 3230566200. Its totient is φ = 3012166080.

The previous prime is 3121312009. The next prime is 3121312063. The reversal of 3121312021 is 1202131213.

It can be written as a sum of positive squares in 4 ways, for example, as 132503121 + 2988808900 = 11511^2 + 54670^2 .

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 3121312021 - 2¹⁵ = 3121279253 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 3121311986 and 3121312004.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (3121316021) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 33991 + ... + 86011.

It is an arithmetic number, because the mean of its divisors is an integer number (403820775).

Almost surely, 2^3121312021 is an apocalyptic number.

It is an amenable number.

3121312021 is a deficient number, since it is larger than the sum of its proper divisors (109254179).

3121312021 is a wasteful number, since it uses less digits than its factorization.

3121312021 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 54119.

The product of its (nonzero) digits is 72, while the sum is 16.

The square root of 3121312021 is about 55868.7034125547. The cubic root of 3121312021 is about 1461.4335111894.

Adding to 3121312021 its reverse (1202131213), we get a palindrome (4323443234).

It can be divided in two parts, 31213 and 12021, that added together give a palindrome (43234).

The spelling of 3121312021 in words is "three billion, one hundred twenty-one million, three hundred twelve thousand, twenty-one".