1981324801 has 4 divisors (see below), whose sum is σ = 1984844592. Its totient is φ = 1977805012.

The previous prime is 1981324759. The next prime is 1981324817. The reversal of 1981324801 is 1084231891.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4, and also an emirpimes, since its reverse is a distinct semiprime: 1084231891 = 23 ⋅47140517.

It is a cyclic number.

It is not a de Polignac number, because 1981324801 - 2²⁵ = 1947770369 is a prime.

It is a super-3 number, since 3×1981324801³ (a number of 29 digits) contains 333 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (1981324831) 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 3 ways as a sum of consecutive naturals, for example, 1759051 + ... + 1760176.

It is an arithmetic number, because the mean of its divisors is an integer number (496211148).

Almost surely, 2^1981324801 is an apocalyptic number.

It is an amenable number.

1981324801 is a deficient number, since it is larger than the sum of its proper divisors (3519791).

1981324801 is an equidigital number, since it uses as much as digits as its factorization.

1981324801 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 3519790.

The product of its (nonzero) digits is 13824, while the sum is 37.

The square root of 1981324801 is about 44512.0747775253. The cubic root of 1981324801 is about 1255.9872341816.

The spelling of 1981324801 in words is "one billion, nine hundred eighty-one million, three hundred twenty-four thousand, eight hundred one".