216721563 has 8 divisors (see below), whose sum is σ = 291237888. Its totient is φ = 143343144.

The previous prime is 216721529. The next prime is 216721567. The reversal of 216721563 is 365127612.

It is a sphenic number, since it is the product of 3 distinct primes.

It is not a de Polignac number, because 216721563 - 2⁶ = 216721499 is a prime.

It is not an unprimeable number, because it can be changed into a prime (216721567) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 284031 + ... + 284792.

It is an arithmetic number, because the mean of its divisors is an integer number (36404736).

Almost surely, 2^216721563 is an apocalyptic number.

216721563 is a deficient number, since it is larger than the sum of its proper divisors (74516325).

216721563 is a wasteful number, since it uses less digits than its factorization.

216721563 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 568953.

The product of its digits is 15120, while the sum is 33.

The square root of 216721563 is about 14721.4660615035. The cubic root of 216721563 is about 600.6673713062.

The spelling of 216721563 in words is "two hundred sixteen million, seven hundred twenty-one thousand, five hundred sixty-three".