216561487 has 16 divisors (see below), whose sum is σ = 244995840. Its totient is φ = 190194048.

The previous prime is 216561479. The next prime is 216561493. The reversal of 216561487 is 784165612.

It is a cyclic number.

It is not a de Polignac number, because 216561487 - 2³ = 216561479 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (216561427) 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, 16638 + ... + 26644.

It is an arithmetic number, because the mean of its divisors is an integer number (15312240).

Almost surely, 2^216561487 is an apocalyptic number.

216561487 is a deficient number, since it is larger than the sum of its proper divisors (28434353).

216561487 is a wasteful number, since it uses less digits than its factorization.

216561487 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 10110.

The product of its digits is 80640, while the sum is 40.

The square root of 216561487 is about 14716.0282345475. The cubic root of 216561487 is about 600.5194455345.

The spelling of 216561487 in words is "two hundred sixteen million, five hundred sixty-one thousand, four hundred eighty-seven".