215128224 has 60 divisors (see below), whose sum is σ = 632693754. Its totient is φ = 71708544.

The previous prime is 215128187. The next prime is 215128229. The reversal of 215128224 is 422821512.

It can be written as a sum of positive squares in only one way, i.e., 170772624 + 44355600 = 13068^2 + 6660^2 .

It is a super-2 number, since 2×215128224² = 92560305522788352, which contains 22 as substring.

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

It is not an unprimeable number, because it can be changed into a prime (215128229) 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 9 ways as a sum of consecutive naturals, for example, 38907 + ... + 44090.

Almost surely, 2^215128224 is an apocalyptic number.

215128224 is a gapful number since it is divisible by the number (24) formed by its first and last digit.

It is an amenable number.

215128224 is an abundant number, since it is smaller than the sum of its proper divisors (417565530).

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

215128224 is an equidigital number, since it uses as much as digits as its factorization.

215128224 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 83019 (or 83002 counting only the distinct ones).

The product of its digits is 2560, while the sum is 27.

The square root of 215128224 is about 14667.2500490037. The cubic root of 215128224 is about 599.1917116054.

Adding to 215128224 its reverse (422821512), we get a palindrome (637949736).

The spelling of 215128224 in words is "two hundred fifteen million, one hundred twenty-eight thousand, two hundred twenty-four".