18999099981 has 12 divisors (see below), whose sum is σ = 27446732508. Its totient is φ = 12664410624.

The previous prime is 18999099979. The next prime is 18999100013.

18999099981 is nontrivially palindromic in base 10.

It can be written as a sum of positive squares in 2 ways, for example, as 6511037481 + 12488062500 = 80691^2 + 111750^2 .

It is not a de Polignac number, because 18999099981 - 2¹ = 18999099979 is a prime.

It is a super-2 number, since 2×18999099981² (a number of 21 digits) contains 22 as substring.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (18999099901) 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 11 ways as a sum of consecutive naturals, for example, 63210 + ... + 204923.

It is an arithmetic number, because the mean of its divisors is an integer number (2287227709).

Almost surely, 2^18999099981 is an apocalyptic number.

It is an amenable number.

18999099981 is a deficient number, since it is larger than the sum of its proper divisors (8447632527).

18999099981 is a wasteful number, since it uses less digits than its factorization.

18999099981 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 276012 (or 276009 counting only the distinct ones).

The product of its (nonzero) digits is 34012224, while the sum is 72.

The spelling of 18999099981 in words is "eighteen billion, nine hundred ninety-nine million, ninety-nine thousand, nine hundred eighty-one".