216556523 has 16 divisors (see below), whose sum is σ = 245747520. Its totient is φ = 189674496.

The previous prime is 216556517. The next prime is 216556553. The reversal of 216556523 is 325655612.

It is a cyclic number.

It is not a de Polignac number, because 216556523 - 2⁸ = 216556267 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (216556553) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 6983 + ... + 21951.

It is an arithmetic number, because the mean of its divisors is an integer number (15359220).

Almost surely, 2^216556523 is an apocalyptic number.

216556523 is a gapful number since it is divisible by the number (23) formed by its first and last digit.

216556523 is a deficient number, since it is larger than the sum of its proper divisors (29190997).

216556523 is a wasteful number, since it uses less digits than its factorization.

216556523 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 15046.

The product of its digits is 54000, while the sum is 35.

The square root of 216556523 is about 14715.8595739427. The cubic root of 216556523 is about 600.5148571512.

The spelling of 216556523 in words is "two hundred sixteen million, five hundred fifty-six thousand, five hundred twenty-three".