216678820 has 12 divisors (see below), whose sum is σ = 455025564. Its totient is φ = 86671520.

The previous prime is 216678799. The next prime is 216678827. The reversal of 216678820 is 28876612.

It can be written as a sum of positive squares in 2 ways, for example, as 142993764 + 73685056 = 11958^2 + 8584^2 .

It is a super-2 number, since 2×216678820² = 93899422073184800, which contains 22 as substring.

It is not an unprimeable number, because it can be changed into a prime (216678827) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 5416951 + ... + 5416990.

It is an arithmetic number, because the mean of its divisors is an integer number (37918797).

Almost surely, 2^216678820 is an apocalyptic number.

216678820 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

216678820 is an abundant number, since it is smaller than the sum of its proper divisors (238346744).

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

216678820 is a wasteful number, since it uses less digits than its factorization.

216678820 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 10833950 (or 10833948 counting only the distinct ones).

The product of its (nonzero) digits is 64512, while the sum is 40.

The square root of 216678820 is about 14720.0142662974. The cubic root of 216678820 is about 600.6278797529.

The spelling of 216678820 in words is "two hundred sixteen million, six hundred seventy-eight thousand, eight hundred twenty".