66920400 has 180 divisors, whose sum is σ = 240615180. Its totient is φ = 17203200.

The previous prime is 66920393. The next prime is 66920419. The reversal of 66920400 is 402966.

It can be written as a sum of positive squares in 6 ways, for example, as 725904 + 66194496 = 852^2 + 8136^2 .

It is a tau number, because it is divible by the number of its divisors (180).

It is a congruent number.

It is an unprimeable number.

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 35 ways as a sum of consecutive naturals, for example, 104080 + ... + 104720.

It is an arithmetic number, because the mean of its divisors is an integer number (1336751).

Almost surely, 2^66920400 is an apocalyptic number.

66920400 is a gapful number since it is divisible by the number (60) formed by its first and last digit.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 66920400, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (120307590).

66920400 is an abundant number, since it is smaller than the sum of its proper divisors (173694780).

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

66920400 is a wasteful number, since it uses less digits than its factorization.

66920400 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 694 (or 680 counting only the distinct ones).

The product of its (nonzero) digits is 2592, while the sum is 27.

The square root of 66920400 is about 8180.4889829398. The cubic root of 66920400 is about 405.9939009171.

The spelling of 66920400 in words is "sixty-six million, nine hundred twenty thousand, four hundred".