216219978 has 96 divisors (see below), whose sum is σ = 534223872. Its totient is φ = 62726400.

The previous prime is 216219973. The next prime is 216219979. The reversal of 216219978 is 879912612.

It is not an unprimeable number, because it can be changed into a prime (216219973) by changing a digit.

It is a polite number, since it can be written in 47 ways as a sum of consecutive naturals, for example, 297051 + ... + 297777.

It is an arithmetic number, because the mean of its divisors is an integer number (5564832).

Almost surely, 2^216219978 is an apocalyptic number.

It is a practical number, because each smaller number is the sum of distinct divisors of 216219978, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (267111936).

216219978 is an abundant number, since it is smaller than the sum of its proper divisors (318003894).

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

216219978 is a wasteful number, since it uses less digits than its factorization.

216219978 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 820 (or 817 counting only the distinct ones).

The product of its digits is 108864, while the sum is 45.

The square root of 216219978 is about 14704.4203557978. The cubic root of 216219978 is about 600.2036142276.

The spelling of 216219978 in words is "two hundred sixteen million, two hundred nineteen thousand, nine hundred seventy-eight".