6521404340 has 96 divisors (see below), whose sum is σ = 15859234944. Its totient is φ = 2226216960.

The previous prime is 6521404339. The next prime is 6521404349. The reversal of 6521404340 is 434041256.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (6521404349) 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 31 ways as a sum of consecutive naturals, for example, 1617407 + ... + 1621433.

It is an arithmetic number, because the mean of its divisors is an integer number (165200364).

Almost surely, 2^6521404340 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 6521404340, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (7929617472).

6521404340 is an abundant number, since it is smaller than the sum of its proper divisors (9337830604).

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

6521404340 is a wasteful number, since it uses less digits than its factorization.

6521404340 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 4497 (or 4495 counting only the distinct ones).

The product of its (nonzero) digits is 11520, while the sum is 29.

The square root of 6521404340 is about 80755.2124633451. The cubic root of 6521404340 is about 1868.3018451746.

Adding to 6521404340 its reverse (434041256), we get a palindrome (6955445596).

The spelling of 6521404340 in words is "six billion, five hundred twenty-one million, four hundred four thousand, three hundred forty".