2191040251 has 2 divisors, whose sum is σ = 2191040252. Its totient is φ = 2191040250.

The previous prime is 2191040249. The next prime is 2191040261. The reversal of 2191040251 is 1520401912.

It is a happy number.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 2191040251 - 2¹ = 2191040249 is a prime.

Together with 2191040249, it forms a pair of twin primes.

It is not a weakly prime, because it can be changed into another prime (2191040261) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 1095520125 + 1095520126.

It is an arithmetic number, because the mean of its divisors is an integer number (1095520126).

Almost surely, 2^2191040251 is an apocalyptic number.

2191040251 is a deficient number, since it is larger than the sum of its proper divisors (1).

2191040251 is an equidigital number, since it uses as much as digits as its factorization.

2191040251 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 720, while the sum is 25.

The square root of 2191040251 is about 46808.5489093606. The cubic root of 2191040251 is about 1298.8234425854.

The spelling of 2191040251 in words is "two billion, one hundred ninety-one million, forty thousand, two hundred fifty-one".