1981324799 has 4 divisors (see below), whose sum is σ = 1981563864. Its totient is φ = 1981085736.

The previous prime is 1981324759. The next prime is 1981324817. The reversal of 1981324799 is 9974231891.

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

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-1981324799 is a prime.

It is a super-3 number, since 3×1981324799³ (a number of 29 digits) contains 333 as substring.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 1981324799.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1981324739) 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, 106637 + ... + 123830.

It is an arithmetic number, because the mean of its divisors is an integer number (495390966).

Almost surely, 2^1981324799 is an apocalyptic number.

1981324799 is a deficient number, since it is larger than the sum of its proper divisors (239065).

1981324799 is an equidigital number, since it uses as much as digits as its factorization.

1981324799 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 239064.

The product of its digits is 979776, while the sum is 53.

The square root of 1981324799 is about 44512.0747550594. The cubic root of 1981324799 is about 1255.9872337590.

The spelling of 1981324799 in words is "one billion, nine hundred eighty-one million, three hundred twenty-four thousand, seven hundred ninety-nine".