216171956 has 72 divisors (see below), whose sum is σ = 510842304. Its totient is φ = 77725440.

The previous prime is 216171953. The next prime is 216171979. The reversal of 216171956 is 659171612.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (216171953) 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 23 ways as a sum of consecutive naturals, for example, 49976 + ... + 54128.

It is an arithmetic number, because the mean of its divisors is an integer number (7095032).

Almost surely, 2^216171956 is an apocalyptic number.

216171956 is a gapful number since it is divisible by the number (26) formed by its first and last digit.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 216171956, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (255421152).

216171956 is an abundant number, since it is smaller than the sum of its proper divisors (294670348).

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

216171956 is a wasteful number, since it uses less digits than its factorization.

216171956 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 4201 (or 4186 counting only the distinct ones).

The product of its digits is 22680, while the sum is 38.

The square root of 216171956 is about 14702.7873547841. The cubic root of 216171956 is about 600.1591762863.

The spelling of 216171956 in words is "two hundred sixteen million, one hundred seventy-one thousand, nine hundred fifty-six".