216181720 has 32 divisors (see below), whose sum is σ = 486835920. Its totient is φ = 86396800.

The previous prime is 216181709. The next prime is 216181729. The reversal of 216181720 is 27181612.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (216181729) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 74619 + ... + 77461.

Almost surely, 2^216181720 is an apocalyptic number.

216181720 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

216181720 is an abundant number, since it is smaller than the sum of its proper divisors (270654200).

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

216181720 is a wasteful number, since it uses less digits than its factorization.

216181720 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 4755 (or 4751 counting only the distinct ones).

The product of its (nonzero) digits is 1344, while the sum is 28.

The square root of 216181720 is about 14703.1193969171. The cubic root of 216181720 is about 600.1682120960.

The spelling of 216181720 in words is "two hundred sixteen million, one hundred eighty-one thousand, seven hundred twenty".