216909836 has 72 divisors (see below), whose sum is σ = 459987696. Its totient is φ = 88231680.

The previous prime is 216909827. The next prime is 216909859. The reversal of 216909836 is 638909612.

It is a Harshad number since it is a multiple of its sum of digits (44).

It is an alternating number because its digits alternate between even and odd.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 782930 + ... + 783206.

It is an arithmetic number, because the mean of its divisors is an integer number (6388718).

Almost surely, 2^216909836 is an apocalyptic number.

216909836 is a gapful number since it is divisible by the number (26) formed by its first and last digit.

It is an amenable number.

216909836 is an abundant number, since it is smaller than the sum of its proper divisors (243077860).

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

216909836 is a wasteful number, since it uses less digits than its factorization.

216909836 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 379 (or 340 counting only the distinct ones).

The product of its (nonzero) digits is 139968, while the sum is 44.

The square root of 216909836 is about 14727.8591791204. The cubic root of 216909836 is about 600.8412606570.

The spelling of 216909836 in words is "two hundred sixteen million, nine hundred nine thousand, eight hundred thirty-six".