3999706121 has 2 divisors, whose sum is σ = 3999706122. Its totient is φ = 3999706120.

The previous prime is 3999706037. The next prime is 3999706147. The reversal of 3999706121 is 1216079993.

3999706121 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 2179489225 + 1820216896 = 46685^2 + 42664^2 .

It is an emirp because it is prime and its reverse (1216079993) is a distict prime.

It is a cyclic number.

It is not a de Polignac number, because 3999706121 - 2¹⁴ = 3999689737 is a prime.

It is not a weakly prime, because it can be changed into another prime (3999706021) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 1999853060 + 1999853061.

It is an arithmetic number, because the mean of its divisors is an integer number (1999853061).

Almost surely, 2^3999706121 is an apocalyptic number.

It is an amenable number.

3999706121 is a deficient number, since it is larger than the sum of its proper divisors (1).

3999706121 is an equidigital number, since it uses as much as digits as its factorization.

3999706121 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 183708, while the sum is 47.

The square root of 3999706121 is about 63243.2298432014. The cubic root of 3999706121 is about 1587.3621756966.

The spelling of 3999706121 in words is "three billion, nine hundred ninety-nine million, seven hundred six thousand, one hundred twenty-one".