3943000021 has 2 divisors, whose sum is σ = 3943000022. Its totient is φ = 3943000020.

The previous prime is 3943000001. The next prime is 3943000037. The reversal of 3943000021 is 1200003493.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 2231523121 + 1711476900 = 47239^2 + 41370^2 .

It is a cyclic number.

It is not a de Polignac number, because 3943000021 - 2¹⁷ = 3942868949 is a prime.

It is a junction number, because it is equal to n+sod(n) for n = 3942999956 and 3943000001.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (3943000001) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 1971500010 + 1971500011.

It is an arithmetic number, because the mean of its divisors is an integer number (1971500011).

Almost surely, 2^3943000021 is an apocalyptic number.

It is an amenable number.

3943000021 is a deficient number, since it is larger than the sum of its proper divisors (1).

3943000021 is an equidigital number, since it uses as much as digits as its factorization.

3943000021 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 648, while the sum is 22.

The square root of 3943000021 is about 62793.3119129737. The cubic root of 3943000021 is about 1579.8247977764.

The spelling of 3943000021 in words is "three billion, nine hundred forty-three million, twenty-one", and thus it is an aban number.