216939408 has 80 divisors (see below), whose sum is σ = 644244480. Its totient is φ = 61619328.

The previous prime is 216939407. The next prime is 216939419. The reversal of 216939408 is 804939612.

It is a Harshad number since it is a multiple of its sum of digits (42).

It is a self number, because there is not a number n which added to its sum of digits gives 216939408.

It is not an unprimeable number, because it can be changed into a prime (216939407) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 58341 + ... + 61947.

It is an arithmetic number, because the mean of its divisors is an integer number (8053056).

Almost surely, 2^216939408 is an apocalyptic number.

216939408 is a gapful number since it is divisible by the number (28) formed by its first and last digit.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 216939408, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (322122240).

216939408 is an abundant number, since it is smaller than the sum of its proper divisors (427305072).

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

216939408 is a wasteful number, since it uses less digits than its factorization.

216939408 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 3804 (or 3798 counting only the distinct ones).

The product of its (nonzero) digits is 93312, while the sum is 42.

The square root of 216939408 is about 14728.8630925812. The cubic root of 216939408 is about 600.8685642757.

The spelling of 216939408 in words is "two hundred sixteen million, nine hundred thirty-nine thousand, four hundred eight".