3121042021 has 4 divisors (see below), whose sum is σ = 3122210572. Its totient is φ = 3119873472.

The previous prime is 3121042013. The next prime is 3121042079. The reversal of 3121042021 is 1202401213.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 227677921 + 2893364100 = 15089^2 + 53790^2 .

It is a cyclic number.

It is not a de Polignac number, because 3121042021 - 2³ = 3121042013 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 3121041986 and 3121042004.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (3121042091) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 580260 + ... + 585613.

It is an arithmetic number, because the mean of its divisors is an integer number (780552643).

Almost surely, 2^3121042021 is an apocalyptic number.

It is an amenable number.

3121042021 is a deficient number, since it is larger than the sum of its proper divisors (1168551).

3121042021 is a wasteful number, since it uses less digits than its factorization.

3121042021 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1168550.

The product of its (nonzero) digits is 96, while the sum is 16.

The square root of 3121042021 is about 55866.2869806111. The cubic root of 3121042021 is about 1461.3913709587.

Adding to 3121042021 its reverse (1202401213), we get a palindrome (4323443234).

The spelling of 3121042021 in words is "three billion, one hundred twenty-one million, forty-two thousand, twenty-one".