216724521 has 16 divisors (see below), whose sum is σ = 316299200. Its totient is φ = 131181120.

The previous prime is 216724499. The next prime is 216724553. The reversal of 216724521 is 125427612.

It is not a de Polignac number, because 216724521 - 2⁵ = 216724489 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (216724121) 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, 43171 + ... + 47928.

It is an arithmetic number, because the mean of its divisors is an integer number (19768700).

Almost surely, 2^216724521 is an apocalyptic number.

It is an amenable number.

216724521 is a deficient number, since it is larger than the sum of its proper divisors (99574679).

216724521 is a wasteful number, since it uses less digits than its factorization.

216724521 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 91176.

The product of its digits is 6720, while the sum is 30.

The square root of 216724521 is about 14721.5665266982. The cubic root of 216724521 is about 600.6701041000.

The spelling of 216724521 in words is "two hundred sixteen million, seven hundred twenty-four thousand, five hundred twenty-one".