216171720 has 64 divisors (see below), whose sum is σ = 720576000. Its totient is φ = 57645504.

The previous prime is 216171701. The next prime is 216171727. The reversal of 216171720 is 27171612.

216171720 is a `hidden beast` number, since 21 + 617 + 1 + 7 + 20 = 666.

It is a hoax number, since the sum of its digits (27) coincides with the sum of the digits of its distinct prime factors.

It is a Harshad number since it is a multiple of its sum of digits (27).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (216171727) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 99000 + ... + 101159.

It is an arithmetic number, because the mean of its divisors is an integer number (11259000).

Almost surely, 2^216171720 is an apocalyptic number.

216171720 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

216171720 is an abundant number, since it is smaller than the sum of its proper divisors (504404280).

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

216171720 is a wasteful number, since it uses less digits than its factorization.

216171720 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 200179 (or 200169 counting only the distinct ones).

The product of its (nonzero) digits is 1176, while the sum is 27.

The square root of 216171720 is about 14702.7793290929. The cubic root of 216171720 is about 600.1589578836.

The spelling of 216171720 in words is "two hundred sixteen million, one hundred seventy-one thousand, seven hundred twenty".