6400069840 has 40 divisors (see below), whose sum is σ = 15132379680. Its totient is φ = 2516635776.

The previous prime is 6400069813. The next prime is 6400069843. The reversal of 6400069840 is 489600046.

It is a tau number, because it is divible by the number of its divisors (40).

It is a self number, because there is not a number n which added to its sum of digits gives 6400069840.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (6400069843) by changing a digit.

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 7 ways as a sum of consecutive naturals, for example, 673254 + ... + 682693.

It is an arithmetic number, because the mean of its divisors is an integer number (378309492).

Almost surely, 2^6400069840 is an apocalyptic number.

It is an amenable number.

6400069840 is an abundant number, since it is smaller than the sum of its proper divisors (8732309840).

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

6400069840 is a wasteful number, since it uses less digits than its factorization.

6400069840 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1356019 (or 1356013 counting only the distinct ones).

The product of its (nonzero) digits is 41472, while the sum is 37.

The square root of 6400069840 is about 80000.4364988092. The cubic root of 6400069840 is about 1856.6422869323.

Adding to 6400069840 its reverse (489600046), we get a palindrome (6889669886).

The spelling of 6400069840 in words is "six billion, four hundred million, sixty-nine thousand, eight hundred forty".