818666251 has 6 divisors (see below), whose sum is σ = 886484940. Its totient is φ = 755691768.

The previous prime is 818666239. The next prime is 818666269. The reversal of 818666251 is 152666818.

It is a de Polignac number, because none of the positive numbers 2^k-818666251 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 818666198 and 818666207.

It is not an unprimeable number, because it can be changed into a prime (818666221) by changing a digit.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 2421921 + ... + 2422258.

It is an arithmetic number, because the mean of its divisors is an integer number (147747490).

Almost surely, 2^818666251 is an apocalyptic number.

818666251 is a deficient number, since it is larger than the sum of its proper divisors (67818689).

818666251 is a wasteful number, since it uses less digits than its factorization.

818666251 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 4844205 (or 4844192 counting only the distinct ones).

The product of its digits is 138240, while the sum is 43.

The square root of 818666251 is about 28612.3443814029. The cubic root of 818666251 is about 935.4824170325.

The spelling of 818666251 in words is "eight hundred eighteen million, six hundred sixty-six thousand, two hundred fifty-one".