3899215921 has 4 divisors (see below), whose sum is σ = 4068747072. Its totient is φ = 3729684772.

The previous prime is 3899215823. The next prime is 3899215933. The reversal of 3899215921 is 1295129983.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4, and also an emirpimes, since its reverse is a distinct semiprime: 1295129983 = 7 ⋅185018569.

It is a cyclic number.

It is not a de Polignac number, because 3899215921 - 2¹¹ = 3899213873 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (3899215961) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 84765541 + ... + 84765586.

It is an arithmetic number, because the mean of its divisors is an integer number (1017186768).

Almost surely, 2^3899215921 is an apocalyptic number.

It is an amenable number.

3899215921 is a deficient number, since it is larger than the sum of its proper divisors (169531151).

3899215921 is a wasteful number, since it uses less digits than its factorization.

3899215921 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 169531150.

The product of its digits is 349920, while the sum is 49.

The square root of 3899215921 is about 62443.7020122926. The cubic root of 3899215921 is about 1573.9554233983.

The spelling of 3899215921 in words is "three billion, eight hundred ninety-nine million, two hundred fifteen thousand, nine hundred twenty-one".