666400106 has 16 divisors (see below), whose sum is σ = 1036146600. Its totient is φ = 321064128.

The previous prime is 666400099. The next prime is 666400109. The reversal of 666400106 is 601004666.

It can be written as a sum of positive squares in 4 ways, for example, as 520980625 + 145419481 = 22825^2 + 12059^2 .

It is a super-2 number, since 2×666400106² = 888178202553622472, which contains 22 as substring.

It is a Harshad number since it is a multiple of its sum of digits (29).

It is not an unprimeable number, because it can be changed into a prime (666400109) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 18236 + ... + 40808.

Almost surely, 2^666400106 is an apocalyptic number.

666400106 is a deficient number, since it is larger than the sum of its proper divisors (369746494).

666400106 is a wasteful number, since it uses less digits than its factorization.

666400106 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 23113.

The product of its (nonzero) digits is 5184, while the sum is 29.

The square root of 666400106 is about 25814.7265335118. The cubic root of 666400106 is about 873.4640181193.

The spelling of 666400106 in words is "six hundred sixty-six million, four hundred thousand, one hundred six".