18216513 has 12 divisors (see below), whose sum is σ = 30071808. Its totient is φ = 10409400.

The previous prime is 18216511. The next prime is 18216557. The reversal of 18216513 is 31561281.

18216513 is a `hidden beast` number, since 1 + 8 + 2 + 1 + 651 + 3 = 666.

It is not a de Polignac number, because 18216513 - 2¹ = 18216511 is a prime.

It is not an unprimeable number, because it can be changed into a prime (18216511) by changing a digit.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 144513 + ... + 144638.

It is an arithmetic number, because the mean of its divisors is an integer number (2505984).

Almost surely, 2^18216513 is an apocalyptic number.

It is an amenable number.

18216513 is a deficient number, since it is larger than the sum of its proper divisors (11855295).

18216513 is a wasteful number, since it uses less digits than its factorization.

18216513 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 289164 (or 289161 counting only the distinct ones).

The product of its digits is 1440, while the sum is 27.

The square root of 18216513 is about 4268.0807162002. The cubic root of 18216513 is about 263.1207404858.

Adding to 18216513 its reverse (31561281), we get a palindrome (49777794).

The spelling of 18216513 in words is "eighteen million, two hundred sixteen thousand, five hundred thirteen".