216766481 has 4 divisors (see below), whose sum is σ = 217738752. Its totient is φ = 215794212.

The previous prime is 216766471. The next prime is 216766493. The reversal of 216766481 is 184667612.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is a cyclic number.

It is not a de Polignac number, because 216766481 - 2²⁶ = 149657617 is a prime.

It is a super-2 number, since 2×216766481² = 93975414570246722, which contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (216766411) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 485801 + ... + 486246.

It is an arithmetic number, because the mean of its divisors is an integer number (54434688).

Almost surely, 2^216766481 is an apocalyptic number.

It is an amenable number.

216766481 is a deficient number, since it is larger than the sum of its proper divisors (972271).

216766481 is an equidigital number, since it uses as much as digits as its factorization.

216766481 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 972270.

The product of its digits is 96768, while the sum is 41.

The square root of 216766481 is about 14722.9915778010. The cubic root of 216766481 is about 600.7088668129.

The spelling of 216766481 in words is "two hundred sixteen million, seven hundred sixty-six thousand, four hundred eighty-one".