216840687 has 16 divisors (see below), whose sum is σ = 333833472. Its totient is φ = 122630400.

The previous prime is 216840671. The next prime is 216840703. The reversal of 216840687 is 786048612.

It is an interprime number because it is at equal distance from previous prime (216840671) and next prime (216840703).

It is not a de Polignac number, because 216840687 - 2⁴ = 216840671 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (216820687) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 51189 + ... + 55262.

It is an arithmetic number, because the mean of its divisors is an integer number (20864592).

Almost surely, 2^216840687 is an apocalyptic number.

216840687 is a deficient number, since it is larger than the sum of its proper divisors (116992785).

216840687 is a wasteful number, since it uses less digits than its factorization.

216840687 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 106558.

The product of its (nonzero) digits is 129024, while the sum is 42.

The square root of 216840687 is about 14725.5114342423. The cubic root of 216840687 is about 600.7774061866. Note that the first 3 decimals are identical.

The spelling of 216840687 in words is "two hundred sixteen million, eight hundred forty thousand, six hundred eighty-seven".