666226665 has 24 divisors (see below), whose sum is σ = 1243624200. Its totient is φ = 327988224.

The previous prime is 666226663. The next prime is 666226669. The reversal of 666226665 is 566622666.

It can be written as a sum of positive squares in 4 ways, for example, as 128867904 + 537358761 = 11352^2 + 23181^2 .

It is not a de Polignac number, because 666226665 - 2¹ = 666226663 is a prime.

It is a Harshad number since it is a multiple of its sum of digits (45).

It is a self number, because there is not a number n which added to its sum of digits gives 666226665.

It is not an unprimeable number, because it can be changed into a prime (666226661) by changing a digit.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 568840 + ... + 570009.

It is an arithmetic number, because the mean of its divisors is an integer number (51817675).

Almost surely, 2^666226665 is an apocalyptic number.

666226665 is a gapful number since it is divisible by the number (65) formed by its first and last digit.

It is an amenable number.

666226665 is a deficient number, since it is larger than the sum of its proper divisors (577397535).

666226665 is a wasteful number, since it uses less digits than its factorization.

666226665 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1138873 (or 1138870 counting only the distinct ones).

The product of its digits is 933120, while the sum is 45.

The square root of 666226665 is about 25811.3669727118. The cubic root of 666226665 is about 873.3882340089.

The spelling of 666226665 in words is "six hundred sixty-six million, two hundred twenty-six thousand, six hundred sixty-five".