215221125 has 64 divisors (see below), whose sum is σ = 412618752. Its totient is φ = 97588800.

The previous prime is 215221033. The next prime is 215221129. The reversal of 215221125 is 521122512.

It is not a de Polignac number, because 215221125 - 2¹² = 215217029 is a prime.

It is a Harshad number since it is a multiple of its sum of digits (21).

It is a Curzon number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (215221129) 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 63 ways as a sum of consecutive naturals, for example, 427624 + ... + 428126.

It is an arithmetic number, because the mean of its divisors is an integer number (6447168).

Almost surely, 2^215221125 is an apocalyptic number.

215221125 is a gapful number since it is divisible by the number (25) formed by its first and last digit.

It is an amenable number.

215221125 is a deficient number, since it is larger than the sum of its proper divisors (197397627).

215221125 is a wasteful number, since it uses less digits than its factorization.

215221125 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 691 (or 681 counting only the distinct ones).

The product of its digits is 400, while the sum is 21.

The square root of 215221125 is about 14670.4166607496. The cubic root of 215221125 is about 599.2779508681.

Adding to 215221125 its reverse (521122512), we get a palindrome (736343637).

The spelling of 215221125 in words is "two hundred fifteen million, two hundred twenty-one thousand, one hundred twenty-five".