66606400 has 168 divisors, whose sum is σ = 197794880. Its totient is φ = 21565440.

The previous prime is 66606389. The next prime is 66606409. The reversal of 66606400 is 460666.

It is a Harshad number since it is a multiple of its sum of digits (28).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (66606409) 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, 212644 + ... + 212956.

Almost surely, 2^66606400 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 66606400, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (98897440).

66606400 is an abundant number, since it is smaller than the sum of its proper divisors (131188480).

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

66606400 is a wasteful number, since it uses less digits than its factorization.

66606400 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 361 (or 346 counting only the distinct ones).

The product of its (nonzero) digits is 5184, while the sum is 28.

The square root of 66606400 is about 8161.2744102867. The cubic root of 66606400 is about 405.3579115213.

The spelling of 66606400 in words is "sixty-six million, six hundred six thousand, four hundred".