216251765 has 4 divisors (see below), whose sum is σ = 259502124. Its totient is φ = 173001408.

The previous prime is 216251759. The next prime is 216251801. The reversal of 216251765 is 567152612.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 136095556 + 80156209 = 11666^2 + 8953^2 .

It is a cyclic number.

It is not a de Polignac number, because 216251765 - 2⁶ = 216251701 is a prime.

It is a Duffinian number.

It is a Curzon number.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 21625172 + ... + 21625181.

It is an arithmetic number, because the mean of its divisors is an integer number (64875531).

Almost surely, 2^216251765 is an apocalyptic number.

It is an amenable number.

216251765 is a deficient number, since it is larger than the sum of its proper divisors (43250359).

216251765 is an equidigital number, since it uses as much as digits as its factorization.

216251765 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 43250358.

The product of its digits is 25200, while the sum is 35.

The square root of 216251765 is about 14705.5011815307. The cubic root of 216251765 is about 600.2330252278.

The spelling of 216251765 in words is "two hundred sixteen million, two hundred fifty-one thousand, seven hundred sixty-five".