2661984399 has 4 divisors (see below), whose sum is σ = 3549312536. Its totient is φ = 1774656264.

The previous prime is 2661984323. The next prime is 2661984401. The reversal of 2661984399 is 9934891662.

It is a happy number.

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

It is not a de Polignac number, because 2661984399 - 2⁹ = 2661983887 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (2661984319) 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 in 3 ways as a sum of consecutive naturals, for example, 443664064 + ... + 443664069.

It is an arithmetic number, because the mean of its divisors is an integer number (887328134).

Almost surely, 2^2661984399 is an apocalyptic number.

2661984399 is a deficient number, since it is larger than the sum of its proper divisors (887328137).

2661984399 is an equidigital number, since it uses as much as digits as its factorization.

2661984399 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 887328136.

The product of its digits is 5038848, while the sum is 57.

The square root of 2661984399 is about 51594.4221694555. The cubic root of 2661984399 is about 1385.9104474372.

The spelling of 2661984399 in words is "two billion, six hundred sixty-one million, nine hundred eighty-four thousand, three hundred ninety-nine".