216464521 has 32 divisors (see below), whose sum is σ = 272643840. Its totient is φ = 167325696.

The previous prime is 216464509. The next prime is 216464527. The reversal of 216464521 is 125464612.

It is a happy number.

It is a cyclic number.

It is not a de Polignac number, because 216464521 - 2¹⁵ = 216431753 is a prime.

It is not an unprimeable number, because it can be changed into a prime (216464527) by changing a digit.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 1209210 + ... + 1209388.

It is an arithmetic number, because the mean of its divisors is an integer number (8520120).

Almost surely, 2^216464521 is an apocalyptic number.

It is an amenable number.

216464521 is a deficient number, since it is larger than the sum of its proper divisors (56179319).

216464521 is a wasteful number, since it uses less digits than its factorization.

216464521 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 433.

The product of its digits is 11520, while the sum is 31.

The square root of 216464521 is about 14712.7332946669. The cubic root of 216464521 is about 600.4298040776.

Subtracting from 216464521 its reverse (125464612), we obtain a palindrome (90999909).

The spelling of 216464521 in words is "two hundred sixteen million, four hundred sixty-four thousand, five hundred twenty-one".