2181091251 has 8 divisors (see below), whose sum is σ = 2912059840. Its totient is φ = 1452091752.

The previous prime is 2181091249. The next prime is 2181091261. The reversal of 2181091251 is 1521901812.

It is a sphenic number, since it is the product of 3 distinct primes.

It is not a de Polignac number, because 2181091251 - 2¹ = 2181091249 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (2181091201) 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 7 ways as a sum of consecutive naturals, for example, 489685 + ... + 494118.

It is an arithmetic number, because the mean of its divisors is an integer number (364007480).

Almost surely, 2^2181091251 is an apocalyptic number.

2181091251 is a deficient number, since it is larger than the sum of its proper divisors (730968589).

2181091251 is an equidigital number, since it uses as much as digits as its factorization.

2181091251 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 984545.

The product of its (nonzero) digits is 1440, while the sum is 30.

The square root of 2181091251 is about 46702.1546719207. The cubic root of 2181091251 is about 1296.8545752866.

The spelling of 2181091251 in words is "two billion, one hundred eighty-one million, ninety-one thousand, two hundred fifty-one".