6645510400 has 81 divisors (see below), whose sum is σ = 16464834421. Its totient is φ = 2655595520.

The previous prime is 6645510337. The next prime is 6645510401. The reversal of 6645510400 is 40155466.

The square root of 6645510400 is 81520.

It is a perfect power (a square), and thus also a powerful number.

It can be written as a sum of positive squares in only one way, i.e., 2392383744 + 4253126656 = 48912^2 + 65216^2 .

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (6645510401) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 8 ways as a sum of consecutive naturals, for example, 6521091 + ... + 6522109.

Almost surely, 2^6645510400 is an apocalyptic number.

6645510400 is the 81520-th square number.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 6645510400

6645510400 is an abundant number, since it is smaller than the sum of its proper divisors (9819324021).

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

6645510400 is an frugal number, since it uses more digits than its factorization.

6645510400 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2064 (or 1026 counting only the distinct ones).

The product of its (nonzero) digits is 14400, while the sum is 31.

The cubic root of 6645510400 is about 1880.0790671439.

Multiplying 6645510400 by its product of nonzero digits (14400), we get a square (95695349760000 = 9782400²).

Adding to 6645510400 its reverse (40155466), we get a palindrome (6685665866).

The spelling of 6645510400 in words is "six billion, six hundred forty-five million, five hundred ten thousand, four hundred".