216921550 has 12 divisors (see below), whose sum is σ = 403474176. Its totient is φ = 86768600.

The previous prime is 216921521. The next prime is 216921587. The reversal of 216921550 is 55129612.

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 2169166 + ... + 2169265.

It is an arithmetic number, because the mean of its divisors is an integer number (33622848).

Almost surely, 2^216921550 is an apocalyptic number.

216921550 is a deficient number, since it is larger than the sum of its proper divisors (186552626).

216921550 is a wasteful number, since it uses less digits than its factorization.

216921550 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 4338443 (or 4338438 counting only the distinct ones).

The product of its (nonzero) digits is 5400, while the sum is 31.

The square root of 216921550 is about 14728.2568554463. The cubic root of 216921550 is about 600.8520764072.

The spelling of 216921550 in words is "two hundred sixteen million, nine hundred twenty-one thousand, five hundred fifty".