18642538 has 8 divisors (see below), whose sum is σ = 28491588. Its totient is φ = 9145344.

The previous prime is 18642517. The next prime is 18642539. The reversal of 18642538 is 83524681.

It is a happy number.

It can be written as a sum of positive squares in 2 ways, for example, as 17280649 + 1361889 = 4157^2 + 1167^2 .

It is a sphenic number, since it is the product of 3 distinct primes.

It is a junction number, because it is equal to n+sod(n) for n = 18642497 and 18642506.

It is not an unprimeable number, because it can be changed into a prime (18642539) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 87831 + ... + 88042.

Almost surely, 2^18642538 is an apocalyptic number.

18642538 is a deficient number, since it is larger than the sum of its proper divisors (9849050).

18642538 is a wasteful number, since it uses less digits than its factorization.

18642538 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 175928.

The product of its digits is 46080, while the sum is 37.

The square root of 18642538 is about 4317.7005454292. The cubic root of 18642538 is about 265.1561344048.

It can be divided in two parts, 186 and 42538, that added together give a palindrome (42724).

The spelling of 18642538 in words is "eighteen million, six hundred forty-two thousand, five hundred thirty-eight".