8393155921 has 4 divisors (see below), whose sum is σ = 8393646244. Its totient is φ = 8392665600.

The previous prime is 8393155919. The next prime is 8393155951. The reversal of 8393155921 is 1295513938.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 2197734400 + 6195421521 = 46880^2 + 78711^2 .

It is a cyclic number.

It is not a de Polignac number, because 8393155921 - 2¹ = 8393155919 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (8393155951) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 218520 + ... + 254041.

It is an arithmetic number, because the mean of its divisors is an integer number (2098411561).

Almost surely, 2^8393155921 is an apocalyptic number.

It is an amenable number.

8393155921 is a deficient number, since it is larger than the sum of its proper divisors (490323).

8393155921 is a wasteful number, since it uses less digits than its factorization.

8393155921 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 490322.

The product of its digits is 291600, while the sum is 46.

The square root of 8393155921 is about 91614.1687786338. The cubic root of 8393155921 is about 2032.2404765598.

The spelling of 8393155921 in words is "eight billion, three hundred ninety-three million, one hundred fifty-five thousand, nine hundred twenty-one".