216538890 has 16 divisors (see below), whose sum is σ = 519693408. Its totient is φ = 57743696.

The previous prime is 216538873. The next prime is 216538891. The reversal of 216538890 is 98835612.

216538890 is digitally balanced in base 3, because in such base it contains all the possibile digits an equal number of times.

It is a super-4 number, since 4×216538890⁴ (a number of 34 digits) contains 4444 as substring.

It is not an unprimeable number, because it can be changed into a prime (216538891) by changing a digit.

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 7 ways as a sum of consecutive naturals, for example, 3608952 + ... + 3609011.

It is an arithmetic number, because the mean of its divisors is an integer number (32480838).

Almost surely, 2^216538890 is an apocalyptic number.

216538890 is an abundant number, since it is smaller than the sum of its proper divisors (303154518).

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

216538890 is a wasteful number, since it uses less digits than its factorization.

216538890 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 7217973.

The product of its (nonzero) digits is 103680, while the sum is 42.

The square root of 216538890 is about 14715.2604462170. The cubic root of 216538890 is about 600.4985578409.

The spelling of 216538890 in words is "two hundred sixteen million, five hundred thirty-eight thousand, eight hundred ninety".