18506531 has 4 divisors (see below), whose sum is σ = 18620232. Its totient is φ = 18392832.

The previous prime is 18506519. The next prime is 18506561. The reversal of 18506531 is 13560581.

It is a semiprime because it is the product of two primes.

It is a cyclic number.

It is not a de Polignac number, because 18506531 - 2¹⁰ = 18505507 is a prime.

It is a super-2 number, since 2×18506531² = 684983379307922, which contains 22 as substring.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 18506494 and 18506503.

It is not an unprimeable number, because it can be changed into a prime (18506561) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 56606 + ... + 56931.

It is an arithmetic number, because the mean of its divisors is an integer number (4655058).

Almost surely, 2^18506531 is an apocalyptic number.

18506531 is a deficient number, since it is larger than the sum of its proper divisors (113701).

18506531 is a wasteful number, since it uses less digits than its factorization.

18506531 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 113700.

The product of its (nonzero) digits is 3600, while the sum is 29.

The square root of 18506531 is about 4301.9217798561. The cubic root of 18506531 is about 264.5097426738.

The spelling of 18506531 in words is "eighteen million, five hundred six thousand, five hundred thirty-one".