3845221891 has 16 divisors (see below), whose sum is σ = 4656381120. Its totient is φ = 3099801600.

The previous prime is 3845221889. The next prime is 3845221907. The reversal of 3845221891 is 1981225483.

It is not a de Polignac number, because 3845221891 - 2¹ = 3845221889 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (3845221801) 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, 166341 + ... + 188041.

It is an arithmetic number, because the mean of its divisors is an integer number (291023820).

Almost surely, 2^3845221891 is an apocalyptic number.

3845221891 is a deficient number, since it is larger than the sum of its proper divisors (811159229).

3845221891 is a wasteful number, since it uses less digits than its factorization.

3845221891 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 23214.

The product of its digits is 138240, while the sum is 43.

The square root of 3845221891 is about 62009.8531767331. The cubic root of 3845221891 is about 1566.6565617627.

The spelling of 3845221891 in words is "three billion, eight hundred forty-five million, two hundred twenty-one thousand, eight hundred ninety-one".