2145555321 has 32 divisors (see below), whose sum is σ = 3531510528. Its totient is φ = 1128314880.

The previous prime is 2145555317. The next prime is 2145555323. The reversal of 2145555321 is 1235555412.

It is not a de Polignac number, because 2145555321 - 2² = 2145555317 is a prime.

It is not an unprimeable number, because it can be changed into a prime (2145555323) by changing a digit.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 80341 + ... + 103661.

It is an arithmetic number, because the mean of its divisors is an integer number (110359704).

Almost surely, 2^2145555321 is an apocalyptic number.

2145555321 is a gapful number since it is divisible by the number (21) formed by its first and last digit.

It is an amenable number.

2145555321 is a deficient number, since it is larger than the sum of its proper divisors (1385955207).

2145555321 is a wasteful number, since it uses less digits than its factorization.

2145555321 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 23681.

The product of its digits is 30000, while the sum is 33.

The square root of 2145555321 is about 46320.1394751786. The cubic root of 2145555321 is about 1289.7728745015.

Subtracting from 2145555321 its reverse (1235555412), we obtain a palindrome (909999909).

The spelling of 2145555321 in words is "two billion, one hundred forty-five million, five hundred fifty-five thousand, three hundred twenty-one".