18216523 has 8 divisors (see below), whose sum is σ = 19707408. Its totient is φ = 16738464.

The previous prime is 18216511. The next prime is 18216557. The reversal of 18216523 is 32561281.

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

It is a cyclic number.

It is not a de Polignac number, because 18216523 - 2²¹ = 16119371 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 18216491 and 18216500.

It is not an unprimeable number, because it can be changed into a prime (18216593) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 136 + ... + 6037.

It is an arithmetic number, because the mean of its divisors is an integer number (2463426).

Almost surely, 2^18216523 is an apocalyptic number.

18216523 is a gapful number since it is divisible by the number (13) formed by its first and last digit.

18216523 is a deficient number, since it is larger than the sum of its proper divisors (1490885).

18216523 is a wasteful number, since it uses less digits than its factorization.

18216523 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 6413.

The product of its digits is 2880, while the sum is 28.

The square root of 18216523 is about 4268.0818876868. The cubic root of 18216523 is about 263.1207886327.

The spelling of 18216523 in words is "eighteen million, two hundred sixteen thousand, five hundred twenty-three".