6531611540 has 24 divisors (see below), whose sum is σ = 13795677000. Its totient is φ = 2597541248.

The previous prime is 6531611519. The next prime is 6531611561. The reversal of 6531611540 is 451161356.

It is an interprime number because it is at equal distance from previous prime (6531611519) and next prime (6531611561).

It can be written as a sum of positive squares in 4 ways, for example, as 2981596816 + 3550014724 = 54604^2 + 59582^2 .

It is a super-2 number, since 2×6531611540² = 85323898618922343200, which contains 22 as substring.

It is a junction number, because it is equal to n+sod(n) for n = 6531611497 and 6531611506.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 940415 + ... + 947334.

It is an arithmetic number, because the mean of its divisors is an integer number (574819875).

Almost surely, 2^6531611540 is an apocalyptic number.

It is an amenable number.

6531611540 is an abundant number, since it is smaller than the sum of its proper divisors (7264065460).

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

6531611540 is a wasteful number, since it uses less digits than its factorization.

6531611540 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1887931 (or 1887929 counting only the distinct ones).

The product of its (nonzero) digits is 10800, while the sum is 32.

The square root of 6531611540 is about 80818.3861506774. The cubic root of 6531611540 is about 1869.2760826659.

Adding to 6531611540 its reverse (451161356), we get a palindrome (6982772896).

The spelling of 6531611540 in words is "six billion, five hundred thirty-one million, six hundred eleven thousand, five hundred forty".