216551213 has 4 divisors (see below), whose sum is σ = 223536768. Its totient is φ = 209565660.

The previous prime is 216551197. The next prime is 216551221. The reversal of 216551213 is 312155612.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is a cyclic number.

It is not a de Polignac number, because 216551213 - 2⁴ = 216551197 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (216551263) 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, 3492731 + ... + 3492792.

It is an arithmetic number, because the mean of its divisors is an integer number (55884192).

Almost surely, 2^216551213 is an apocalyptic number.

It is an amenable number.

216551213 is a deficient number, since it is larger than the sum of its proper divisors (6985555).

216551213 is an equidigital number, since it uses as much as digits as its factorization.

216551213 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 6985554.

The product of its digits is 1800, while the sum is 26.

The square root of 216551213 is about 14715.6791552412. The cubic root of 216551213 is about 600.5099488715.

The spelling of 216551213 in words is "two hundred sixteen million, five hundred fifty-one thousand, two hundred thirteen".