18011987636 has 12 divisors (see below), whose sum is σ = 31535237412. Its totient is φ = 9001919808.

The previous prime is 18011987569. The next prime is 18011987639. The reversal of 18011987636 is 63678911081.

It can be written as a sum of positive squares in 2 ways, for example, as 14788019236 + 3223968400 = 121606^2 + 56780^2 .

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (18011987639) 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, 1008545 + ... + 1026248.

It is an arithmetic number, because the mean of its divisors is an integer number (2627936451).

Almost surely, 2^18011987636 is an apocalyptic number.

It is an amenable number.

18011987636 is a deficient number, since it is larger than the sum of its proper divisors (13523249776).

18011987636 is a wasteful number, since it uses less digits than its factorization.

18011987636 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2037010 (or 2037008 counting only the distinct ones).

The product of its (nonzero) digits is 435456, while the sum is 50.

The spelling of 18011987636 in words is "eighteen billion, eleven million, nine hundred eighty-seven thousand, six hundred thirty-six".