19488061981 has 4 divisors (see below), whose sum is σ = 19489539132. Its totient is φ = 19486584832.

The previous prime is 19488061933. The next prime is 19488061997. The reversal of 19488061981 is 18916088491.

It is a happy number.

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

It can be written as a sum of positive squares in 2 ways, for example, as 7549003225 + 11939058756 = 86885^2 + 109266^2 .

It is a cyclic number.

It is not a de Polignac number, because 19488061981 - 2¹⁵ = 19488029213 is a prime.

It is a super-2 number, since 2×19488061981² (a number of 21 digits) contains 22 as substring.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (19488061381) 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, 718606 + ... + 745231.

It is an arithmetic number, because the mean of its divisors is an integer number (4872384783).

Almost surely, 2^19488061981 is an apocalyptic number.

It is an amenable number.

19488061981 is a deficient number, since it is larger than the sum of its proper divisors (1477151).

19488061981 is a wasteful number, since it uses less digits than its factorization.

19488061981 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1477150.

The product of its (nonzero) digits is 995328, while the sum is 55.

The spelling of 19488061981 in words is "nineteen billion, four hundred eighty-eight million, sixty-one thousand, nine hundred eighty-one".