216557743209 has 32 divisors (see below), whose sum is σ = 306669966336. Its totient is φ = 135461652480.

The previous prime is 216557743187. The next prime is 216557743217. The reversal of 216557743209 is 902347755612.

It is not a de Polignac number, because 216557743209 - 2⁵ = 216557743177 is a prime.

It is a super-2 number, since 2×216557743209² (a number of 23 digits) contains 22 as substring.

It is a Harshad number since it is a multiple of its sum of digits (51).

It is not an unprimeable number, because it can be changed into a prime (216557743249) by changing a digit.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 23429829 + ... + 23439069.

It is an arithmetic number, because the mean of its divisors is an integer number (9583436448).

Almost surely, 2^216557743209 is an apocalyptic number.

It is an amenable number.

216557743209 is a deficient number, since it is larger than the sum of its proper divisors (90112223127).

216557743209 is a wasteful number, since it uses less digits than its factorization.

216557743209 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 10625.

The product of its (nonzero) digits is 3175200, while the sum is 51.

The spelling of 216557743209 in words is "two hundred sixteen billion, five hundred fifty-seven million, seven hundred forty-three thousand, two hundred nine".