3999633653021 has 2 divisors, whose sum is σ = 3999633653022. Its totient is φ = 3999633653020.

The previous prime is 3999633653003. The next prime is 3999633653089. The reversal of 3999633653021 is 1203563369993.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 2811557632900 + 1188076020121 = 1676770^2 + 1089989^2 .

It is a cyclic number.

It is not a de Polignac number, because 3999633653021 - 2³⁴ = 3982453783837 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (3999633653321) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 1999816826510 + 1999816826511.

It is an arithmetic number, because the mean of its divisors is an integer number (1999816826511).

Almost surely, 2^{3999633653021} is an apocalyptic number.

It is an amenable number.

3999633653021 is a deficient number, since it is larger than the sum of its proper divisors (1).

3999633653021 is an equidigital number, since it uses as much as digits as its factorization.

3999633653021 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 21257640, while the sum is 59.

The spelling of 3999633653021 in words is "three trillion, nine hundred ninety-nine billion, six hundred thirty-three million, six hundred fifty-three thousand, twenty-one".