216421356 has 48 divisors (see below), whose sum is σ = 540249696. Its totient is φ = 67190784.

The previous prime is 216421349. The next prime is 216421391. The reversal of 216421356 is 653124612.

It is an unprimeable number.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 14320 + ... + 25256.

It is an arithmetic number, because the mean of its divisors is an integer number (11255202).

Almost surely, 2^216421356 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 216421356, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (270124848).

216421356 is an abundant number, since it is smaller than the sum of its proper divisors (323828340).

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

216421356 is a wasteful number, since it uses less digits than its factorization.

216421356 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 11058 (or 11056 counting only the distinct ones).

The product of its digits is 8640, while the sum is 30.

The square root of 216421356 is about 14711.2662949183. The cubic root of 216421356 is about 600.3898910312.

Adding to 216421356 its reverse (653124612), we get a palindrome (869545968).

The spelling of 216421356 in words is "two hundred sixteen million, four hundred twenty-one thousand, three hundred fifty-six".