18359437009 has 3 divisors (see below), whose sum is σ = 18359572507. Its totient is φ = 18359301512.

The previous prime is 18359437003. The next prime is 18359437013. The reversal of 18359437009 is 90073495381.

The square root of 18359437009 is 135497.

It is a perfect power (a square), and thus also a powerful number.

It is a semiprime because it is the product of two primes, and also a brilliant number, because the two primes have the same length, and also an emirpimes, since its reverse is a distinct semiprime: 90073495381 = 10709 ⋅8411009.

It can be written as a sum of positive squares in only one way, i.e., 10236380625 + 8123056384 = 101175^2 + 90128^2 .

It is not a de Polignac number, because 18359437009 - 2⁷ = 18359436881 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (18359437003) by changing a digit.

It is a polite number, since it can be written in 2 ways as a sum of consecutive naturals, for example, 67749 + ... + 203245.

Almost surely, 2^18359437009 is an apocalyptic number.

18359437009 is the 135497-th square number.

18359437009 is the 67749-th centered octagonal number.

It is an amenable number.

18359437009 is a deficient number, since it is larger than the sum of its proper divisors (135498).

18359437009 is an frugal number, since it uses more digits than its factorization.

18359437009 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 270994 (or 135497 counting only the distinct ones).

The product of its (nonzero) digits is 816480, while the sum is 49.

Multiplying 18359437009 by its sum of digits (49), we get a square (899612413441 = 948479²).

The spelling of 18359437009 in words is "eighteen billion, three hundred fifty-nine million, four hundred thirty-seven thousand, nine".