2181355251 has 4 divisors (see below), whose sum is σ = 2908473672. Its totient is φ = 1454236832.

The previous prime is 2181355199. The next prime is 2181355271. The reversal of 2181355251 is 1525531812.

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

It is a cyclic number.

It is not a de Polignac number, because 2181355251 - 2¹¹ = 2181353203 is a prime.

It is not an unprimeable number, because it can be changed into a prime (2181355271) 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, 363559206 + ... + 363559211.

It is an arithmetic number, because the mean of its divisors is an integer number (727118418).

Almost surely, 2^2181355251 is an apocalyptic number.

2181355251 is a deficient number, since it is larger than the sum of its proper divisors (727118421).

2181355251 is an equidigital number, since it uses as much as digits as its factorization.

2181355251 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 727118420.

The product of its digits is 12000, while the sum is 33.

The square root of 2181355251 is about 46704.9810084535. The cubic root of 2181355251 is about 1296.9068970766.

The spelling of 2181355251 in words is "two billion, one hundred eighty-one million, three hundred fifty-five thousand, two hundred fifty-one".