666402726 has 32 divisors (see below), whose sum is σ = 1456507008. Its totient is φ = 201587840.

The previous prime is 666402689. The next prime is 666402727. The reversal of 666402726 is 627204666.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (666402727) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 30625 + ... + 47651.

It is an arithmetic number, because the mean of its divisors is an integer number (45515844).

Almost surely, 2^666402726 is an apocalyptic number.

666402726 is a gapful number since it is divisible by the number (66) formed by its first and last digit.

666402726 is an abundant number, since it is smaller than the sum of its proper divisors (790104282).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

666402726 is a wasteful number, since it uses less digits than its factorization.

666402726 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 17636.

The product of its (nonzero) digits is 145152, while the sum is 39.

The square root of 666402726 is about 25814.7772796900. Note that the first 3 decimals coincide. The cubic root of 666402726 is about 873.4651628134.

The spelling of 666402726 in words is "six hundred sixty-six million, four hundred two thousand, seven hundred twenty-six".