215531125 has 16 divisors (see below), whose sum is σ = 274066416. Its totient is φ = 169166400.

The previous prime is 215531123. The next prime is 215531149. The reversal of 215531125 is 521135512.

It can be written as a sum of positive squares in 8 ways, for example, as 69072721 + 146458404 = 8311^2 + 12102^2 .

It is not a de Polignac number, because 215531125 - 2¹ = 215531123 is a prime.

It is a Harshad number since it is a multiple of its sum of digits (25).

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 215531125.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (215531123) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 9642 + ... + 22891.

It is an arithmetic number, because the mean of its divisors is an integer number (17129151).

Almost surely, 2^215531125 is an apocalyptic number.

215531125 is a gapful number since it is divisible by the number (25) formed by its first and last digit.

It is an amenable number.

215531125 is a deficient number, since it is larger than the sum of its proper divisors (58535291).

215531125 is an equidigital number, since it uses as much as digits as its factorization.

215531125 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 32601 (or 32591 counting only the distinct ones).

The product of its digits is 1500, while the sum is 25.

The square root of 215531125 is about 14680.9783393342. The cubic root of 215531125 is about 599.5655419678.

Adding to 215531125 its reverse (521135512), we get a palindrome (736666637).

The spelling of 215531125 in words is "two hundred fifteen million, five hundred thirty-one thousand, one hundred twenty-five".