216651234665 has 4 divisors (see below), whose sum is σ = 259981481604. Its totient is φ = 173320987728.

The previous prime is 216651234661. The next prime is 216651234671. The reversal of 216651234665 is 566432156612.

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 23062674496 + 193588560169 = 151864^2 + 439987^2 .

It is a cyclic number.

It is not a de Polignac number, because 216651234665 - 2² = 216651234661 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (216651234661) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 21665123462 + ... + 21665123471.

It is an arithmetic number, because the mean of its divisors is an integer number (64995370401).

Almost surely, 2^216651234665 is an apocalyptic number.

It is an amenable number.

216651234665 is a deficient number, since it is larger than the sum of its proper divisors (43330246939).

216651234665 is an equidigital number, since it uses as much as digits as its factorization.

216651234665 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 43330246938.

The product of its digits is 1555200, while the sum is 47.

The spelling of 216651234665 in words is "two hundred sixteen billion, six hundred fifty-one million, two hundred thirty-four thousand, six hundred sixty-five".