66642400 has 72 divisors (see below), whose sum is σ = 177504264. Its totient is φ = 24230400.

The previous prime is 66642379. The next prime is 66642409. The reversal of 66642400 is 424666.

It is a zygodrome in base 2.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (66642409) by changing a digit.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 5014 + ... + 12586.

It is an arithmetic number, because the mean of its divisors is an integer number (2465337).

Almost surely, 2^66642400 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 66642400, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (88752132).

66642400 is an abundant number, since it is smaller than the sum of its proper divisors (110861864).

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

66642400 is a wasteful number, since it uses less digits than its factorization.

66642400 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 7604 (or 7591 counting only the distinct ones).

The product of its (nonzero) digits is 6912, while the sum is 28.

The square root of 66642400 is about 8163.4796502472. The cubic root of 66642400 is about 405.4309288115.

The spelling of 66642400 in words is "sixty-six million, six hundred forty-two thousand, four hundred".