216253721 has 8 divisors (see below), whose sum is σ = 226243584. Its totient is φ = 206488480.

The previous prime is 216253693. The next prime is 216253729. The reversal of 216253721 is 127352612.

It is a happy number.

216253721 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

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 216253721 - 2⁶ = 216253657 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (216253729) 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, 54185 + ... + 58038.

It is an arithmetic number, because the mean of its divisors is an integer number (28280448).

Almost surely, 2^216253721 is an apocalyptic number.

It is an amenable number.

216253721 is a deficient number, since it is larger than the sum of its proper divisors (9989863).

216253721 is a wasteful number, since it uses less digits than its factorization.

216253721 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 112311.

The product of its digits is 5040, while the sum is 29.

The square root of 216253721 is about 14705.5676871041. The cubic root of 216253721 is about 600.2348349275.

The spelling of 216253721 in words is "two hundred sixteen million, two hundred fifty-three thousand, seven hundred twenty-one".