216921528 has 96 divisors (see below), whose sum is σ = 609813360. Its totient is φ = 69603840.

The previous prime is 216921521. The next prime is 216921587. The reversal of 216921528 is 825129612.

It is a Harshad number since it is a multiple of its sum of digits (36).

It is a junction number, because it is equal to n+sod(n) for n = 216921492 and 216921501.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (216921521) by changing a digit.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 284668 + ... + 285428.

Almost surely, 2^216921528 is an apocalyptic number.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 216921528, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (304906680).

216921528 is an abundant number, since it is smaller than the sum of its proper divisors (392891832).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

216921528 is a wasteful number, since it uses less digits than its factorization.

216921528 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 917 (or 910 counting only the distinct ones).

The product of its digits is 17280, while the sum is 36.

The square root of 216921528 is about 14728.2561085826. The cubic root of 216921528 is about 600.8520560946.

It can be divided in two parts, 21692 and 1528, that added together give a triangular number (23220 = T₂₁₅).

The spelling of 216921528 in words is "two hundred sixteen million, nine hundred twenty-one thousand, five hundred twenty-eight".