216783890 has 8 divisors (see below), whose sum is σ = 390211020. Its totient is φ = 86713552.

The previous prime is 216783883. The next prime is 216783923. The reversal of 216783890 is 98387612.

It can be written as a sum of positive squares in 2 ways, for example, as 216766729 + 17161 = 14723^2 + 131^2 .

It is a sphenic number, since it is the product of 3 distinct primes.

It is a super-3 number, since 3×216783890³ (a number of 26 digits) contains 333 as substring.

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

It is a Curzon number.

It is an unprimeable number.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 10839185 + ... + 10839204.

Almost surely, 2^216783890 is an apocalyptic number.

216783890 is a deficient number, since it is larger than the sum of its proper divisors (173427130).

216783890 is a wasteful number, since it uses less digits than its factorization.

216783890 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 21678396.

The product of its (nonzero) digits is 145152, while the sum is 44.

The square root of 216783890 is about 14723.5827840916. The cubic root of 216783890 is about 600.7249478058.

The spelling of 216783890 in words is "two hundred sixteen million, seven hundred eighty-three thousand, eight hundred ninety".