1981398099 has 8 divisors (see below), whose sum is σ = 2642207680. Its totient is φ = 1320760296.

The previous prime is 1981398031. The next prime is 1981398101. The reversal of 1981398099 is 9908931891.

It is a sphenic number, since it is the product of 3 distinct primes.

It is not a de Polignac number, because 1981398099 - 2²⁴ = 1964620883 is a prime.

It is a super-3 number, since 3×1981398099³ (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 (1981394099) 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 7 ways as a sum of consecutive naturals, for example, 13057 + ... + 64290.

It is an arithmetic number, because the mean of its divisors is an integer number (330275960).

Almost surely, 2^1981398099 is an apocalyptic number.

1981398099 is a deficient number, since it is larger than the sum of its proper divisors (660809581).

1981398099 is an equidigital number, since it uses as much as digits as its factorization.

1981398099 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 85889.

The product of its (nonzero) digits is 1259712, while the sum is 57.

The square root of 1981398099 is about 44512.8981195338. The cubic root of 1981398099 is about 1256.0027221718.

The spelling of 1981398099 in words is "one billion, nine hundred eighty-one million, three hundred ninety-eight thousand, ninety-nine".