3865900021 has 2 divisors, whose sum is σ = 3865900022. Its totient is φ = 3865900020.

The previous prime is 3865900009. The next prime is 3865900061. The reversal of 3865900021 is 1200095683.

3865900021 is digitally balanced in base 3, because in such base it contains all the possibile digits an equal number of times.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 3323522500 + 542377521 = 57650^2 + 23289^2 .

It is a cyclic number.

It is not a de Polignac number, because 3865900021 - 2⁹ = 3865899509 is a prime.

It is a self number, because there is not a number n which added to its sum of digits gives 3865900021.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (3865900061) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 1932950010 + 1932950011.

It is an arithmetic number, because the mean of its divisors is an integer number (1932950011).

Almost surely, 2^3865900021 is an apocalyptic number.

It is an amenable number.

3865900021 is a deficient number, since it is larger than the sum of its proper divisors (1).

3865900021 is an equidigital number, since it uses as much as digits as its factorization.

3865900021 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 12960, while the sum is 34.

The square root of 3865900021 is about 62176.3622367858. The cubic root of 3865900021 is about 1569.4598356777.

The spelling of 3865900021 in words is "three billion, eight hundred sixty-five million, nine hundred thousand, twenty-one".