215281920 has 144 divisors (see below), whose sum is σ = 785877120. Its totient is φ = 49201152.

The previous prime is 215281901. The next prime is 215281933. The reversal of 215281920 is 29182512.

It is a Harshad number since it is a multiple of its sum of digits (30).

It is an unprimeable number.

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, 22876 + ... + 30884.

It is an arithmetic number, because the mean of its divisors is an integer number (5457480).

Almost surely, 2^215281920 is an apocalyptic number.

215281920 is a gapful number since it is divisible by the number (20) 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 215281920, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (392938560).

215281920 is an abundant number, since it is smaller than the sum of its proper divisors (570595200).

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

215281920 is an equidigital number, since it uses as much as digits as its factorization.

215281920 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 8040 (or 8026 counting only the distinct ones).

The product of its (nonzero) digits is 2880, while the sum is 30.

The square root of 215281920 is about 14672.4885414847. The cubic root of 215281920 is about 599.3343729519.

The spelling of 215281920 in words is "two hundred fifteen million, two hundred eighty-one thousand, nine hundred twenty".