18509787990 has 48 divisors (see below), whose sum is σ = 48367332000. Its totient is φ = 4911134976.

The previous prime is 18509787971. The next prime is 18509787997. The reversal of 18509787990 is 9978790581.

It is a super-2 number, since 2×18509787990² (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 (18509787997) by changing a digit.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 498835 + ... + 534654.

It is an arithmetic number, because the mean of its divisors is an integer number (1007652750).

Almost surely, 2^18509787990 is an apocalyptic number.

18509787990 is a gapful number since it is divisible by the number (10) formed by its first and last digit.

18509787990 is an abundant number, since it is smaller than the sum of its proper divisors (29857544010).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

18509787990 is a wasteful number, since it uses less digits than its factorization.

18509787990 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1033701 (or 1033698 counting only the distinct ones).

The product of its (nonzero) digits is 11430720, while the sum is 63.

The spelling of 18509787990 in words is "eighteen billion, five hundred nine million, seven hundred eighty-seven thousand, nine hundred ninety".