216165521 has 8 divisors (see below), whose sum is σ = 253956864. Its totient is φ = 181397520.

The previous prime is 216165503. The next prime is 216165529. The reversal of 216165521 is 125561612.

It is a happy number.

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 216165521 - 2¹⁰ = 216164497 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (216165529) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 755681 + ... + 755966.

It is an arithmetic number, because the mean of its divisors is an integer number (31744608).

Almost surely, 2^216165521 is an apocalyptic number.

It is an amenable number.

216165521 is a deficient number, since it is larger than the sum of its proper divisors (37791343).

216165521 is a wasteful number, since it uses less digits than its factorization.

216165521 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1511671.

The product of its digits is 3600, while the sum is 29.

The square root of 216165521 is about 14702.5685170993. The cubic root of 216165521 is about 600.1532210540.

The spelling of 216165521 in words is "two hundred sixteen million, one hundred sixty-five thousand, five hundred twenty-one".