216581965 has 8 divisors (see below), whose sum is σ = 268282368. Its totient is φ = 167676240.

The previous prime is 216581957. The next prime is 216582011. The reversal of 216581965 is 569185612.

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

It is not a de Polignac number, because 216581965 - 2³ = 216581957 is a prime.

It is a super-2 number, since 2×216581965² = 93815495126522450, which contains 22 as substring.

It is a Duffinian number.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 698497 + ... + 698806.

It is an arithmetic number, because the mean of its divisors is an integer number (33535296).

Almost surely, 2^216581965 is an apocalyptic number.

It is an amenable number.

216581965 is a deficient number, since it is larger than the sum of its proper divisors (51700403).

216581965 is a wasteful number, since it uses less digits than its factorization.

216581965 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1397339.

The product of its digits is 129600, while the sum is 43.

The square root of 216581965 is about 14716.7239900733. The cubic root of 216581965 is about 600.5383732607.

The spelling of 216581965 in words is "two hundred sixteen million, five hundred eighty-one thousand, nine hundred sixty-five".