666436400 has 120 divisors (see below), whose sum is σ = 1926305280. Its totient is φ = 216449280.

The previous prime is 666436399. The next prime is 666436409. The reversal of 666436400 is 4634666.

It is a Harshad number since it is a multiple of its sum of digits (35).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (666436409) 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 23 ways as a sum of consecutive naturals, for example, 46937 + ... + 59463.

It is an arithmetic number, because the mean of its divisors is an integer number (16052544).

Almost surely, 2^666436400 is an apocalyptic number.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 666436400, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (963152640).

666436400 is an abundant number, since it is smaller than the sum of its proper divisors (1259868880).

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

666436400 is a wasteful number, since it uses less digits than its factorization.

666436400 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 12571 (or 12560 counting only the distinct ones).

The product of its (nonzero) digits is 62208, while the sum is 35.

The square root of 666436400 is about 25815.4294947808. The cubic root of 666436400 is about 873.4798749233.

The spelling of 666436400 in words is "six hundred sixty-six million, four hundred thirty-six thousand, four hundred".