66400900 has 18 divisors (see below), whose sum is σ = 144090170. Its totient is φ = 26560320.

The previous prime is 66400897. The next prime is 66400933. The reversal of 66400900 is 900466.

66400900 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It can be written as a sum of positive squares in 3 ways, for example, as 1887876 + 64513024 = 1374^2 + 8032^2 .

It is a Harshad number since it is a multiple of its sum of digits (25).

It is a congruent number.

It is an unprimeable number.

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 5 ways as a sum of consecutive naturals, for example, 331905 + ... + 332104.

Almost surely, 2^66400900 is an apocalyptic number.

It is an amenable number.

66400900 is an abundant number, since it is smaller than the sum of its proper divisors (77689270).

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

66400900 is a wasteful number, since it uses less digits than its factorization.

66400900 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 664023 (or 664016 counting only the distinct ones).

The product of its (nonzero) digits is 1296, while the sum is 25.

The square root of 66400900 is about 8148.6747388763. The cubic root of 66400900 is about 404.9405999355.

The spelling of 66400900 in words is "sixty-six million, four hundred thousand, nine hundred".