3867531281821 has 16 divisors (see below), whose sum is σ = 4067154149760. Its totient is φ = 3672345942720.

The previous prime is 3867531281749. The next prime is 3867531281851. The reversal of 3867531281821 is 1281821357683.

It is a happy number.

It is a cyclic number.

It is not a de Polignac number, because 3867531281821 - 2¹³ = 3867531273629 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (3867531281851) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 10724976 + ... + 11079718.

It is an arithmetic number, because the mean of its divisors is an integer number (254197134360).

Almost surely, 2^{3867531281821} is an apocalyptic number.

It is an amenable number.

3867531281821 is a deficient number, since it is larger than the sum of its proper divisors (199622867939).

3867531281821 is a wasteful number, since it uses less digits than its factorization.

3867531281821 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 360996.

The product of its digits is 3870720, while the sum is 55.

The spelling of 3867531281821 in words is "three trillion, eight hundred sixty-seven billion, five hundred thirty-one million, two hundred eighty-one thousand, eight hundred twenty-one".