216764665 has 8 divisors (see below), whose sum is σ = 280126728. Its totient is φ = 160072320.

The previous prime is 216764651. The next prime is 216764701. The reversal of 216764665 is 566467612.

It is a happy number.

It can be written as a sum of positive squares in 4 ways, for example, as 3283344 + 213481321 = 1812^2 + 14611^2 .

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

It is not a de Polignac number, because 216764665 - 2²⁵ = 183210233 is a prime.

It is a Duffinian 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, 1667356 + ... + 1667485.

It is an arithmetic number, because the mean of its divisors is an integer number (35015841).

Almost surely, 2^216764665 is an apocalyptic number.

It is an amenable number.

216764665 is a deficient number, since it is larger than the sum of its proper divisors (63362063).

216764665 is a wasteful number, since it uses less digits than its factorization.

216764665 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 3334859.

The product of its digits is 362880, while the sum is 43.

The square root of 216764665 is about 14722.9299054230. The cubic root of 216764665 is about 600.7071892928.

The spelling of 216764665 in words is "two hundred sixteen million, seven hundred sixty-four thousand, six hundred sixty-five".