3121840921 has 2 divisors, whose sum is σ = 3121840922. Its totient is φ = 3121840920.

The previous prime is 3121840877. The next prime is 3121840933. The reversal of 3121840921 is 1290481213.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 3117658896 + 4182025 = 55836^2 + 2045^2 .

It is a cyclic number.

It is not a de Polignac number, because 3121840921 - 2¹¹ = 3121838873 is a prime.

It is not a weakly prime, because it can be changed into another prime (3121840021) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 1560920460 + 1560920461.

It is an arithmetic number, because the mean of its divisors is an integer number (1560920461).

Almost surely, 2^3121840921 is an apocalyptic number.

It is an amenable number.

3121840921 is a deficient number, since it is larger than the sum of its proper divisors (1).

3121840921 is an equidigital number, since it uses as much as digits as its factorization.

3121840921 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 3456, while the sum is 31.

The square root of 3121840921 is about 55873.4366313725. The cubic root of 3121840921 is about 1461.5160521770.

The spelling of 3121840921 in words is "three billion, one hundred twenty-one million, eight hundred forty thousand, nine hundred twenty-one".