215871645 has 16 divisors (see below), whose sum is σ = 376794432. Its totient is φ = 104664960.

The previous prime is 215871613. The next prime is 215871671. The reversal of 215871645 is 546178512.

It is not a de Polignac number, because 215871645 - 2⁵ = 215871613 is a prime.

It is a congruent number.

It is an unprimeable number.

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, 653992 + ... + 654321.

It is an arithmetic number, because the mean of its divisors is an integer number (23549652).

Almost surely, 2^215871645 is an apocalyptic number.

It is an amenable number.

215871645 is a deficient number, since it is larger than the sum of its proper divisors (160922787).

215871645 is a wasteful number, since it uses less digits than its factorization.

215871645 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1308332.

The product of its digits is 67200, while the sum is 39.

The square root of 215871645 is about 14692.5710820128. The cubic root of 215871645 is about 599.8811292289.

It can be divided in two parts, 21587 and 1645, that added together give a palindrome (23232).

The spelling of 215871645 in words is "two hundred fifteen million, eight hundred seventy-one thousand, six hundred forty-five".