2191431409 has 4 divisors (see below), whose sum is σ = 2191526260. Its totient is φ = 2191336560.

The previous prime is 2191431397. The next prime is 2191431479. The reversal of 2191431409 is 9041341912.

2191431409 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a semiprime because it is the product of two primes, and also a brilliant number, because the two primes have the same length.

It can be written as a sum of positive squares in 2 ways, for example, as 1424307600 + 767123809 = 37740^2 + 27697^2 .

It is a cyclic number.

It is not a de Polignac number, because 2191431409 - 2¹⁷ = 2191300337 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (2191431479) 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, 12319 + ... + 67339.

It is an arithmetic number, because the mean of its divisors is an integer number (547881565).

Almost surely, 2^2191431409 is an apocalyptic number.

It is an amenable number.

2191431409 is a deficient number, since it is larger than the sum of its proper divisors (94851).

2191431409 is an equidigital number, since it uses as much as digits as its factorization.

2191431409 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 94850.

The product of its (nonzero) digits is 7776, while the sum is 34.

The square root of 2191431409 is about 46812.7269981145. The cubic root of 2191431409 is about 1298.9007293065.

The spelling of 2191431409 in words is "two billion, one hundred ninety-one million, four hundred thirty-one thousand, four hundred nine".