215138187 has 40 divisors (see below), whose sum is σ = 354665520. Its totient is φ = 128874240.

The previous prime is 215138173. The next prime is 215138191. The reversal of 215138187 is 781831512.

It is not a de Polignac number, because 215138187 - 2⁶ = 215138123 is a prime.

It is not an unprimeable number, because it can be changed into a prime (215138107) 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 39 ways as a sum of consecutive naturals, for example, 77943 + ... + 80655.

It is an arithmetic number, because the mean of its divisors is an integer number (8866638).

Almost surely, 2^215138187 is an apocalyptic number.

215138187 is a gapful number since it is divisible by the number (27) formed by its first and last digit.

215138187 is a deficient number, since it is larger than the sum of its proper divisors (139527333).

215138187 is a wasteful number, since it uses less digits than its factorization.

215138187 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2825 (or 2816 counting only the distinct ones).

The product of its digits is 13440, while the sum is 36.

The square root of 215138187 is about 14667.5896792895. The cubic root of 215138187 is about 599.2009613678.

Adding to 215138187 its reverse (781831512), we get a palindrome (996969699).

The spelling of 215138187 in words is "two hundred fifteen million, one hundred thirty-eight thousand, one hundred eighty-seven".