531540656561 has 16 divisors (see below), whose sum is σ = 542571665664. Its totient is φ = 520617072384.

The previous prime is 531540656527. The next prime is 531540656579. The reversal of 531540656561 is 165656045135.

It is a cyclic number.

It is not a de Polignac number, because 531540656561 - 2²⁶ = 531473547697 is a prime.

It is a Smith number, since the sum of its digits (47) coincides with the sum of the digits of its prime factors. Since it is squarefree, it is also a hoax number.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (531540656501) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 12938525 + ... + 12979541.

It is an arithmetic number, because the mean of its divisors is an integer number (33910729104).

Almost surely, 2^531540656561 is an apocalyptic number.

It is an amenable number.

531540656561 is a deficient number, since it is larger than the sum of its proper divisors (11031009103).

531540656561 is a wasteful number, since it uses less digits than its factorization.

531540656561 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 42320.

The product of its (nonzero) digits is 1620000, while the sum is 47.

The spelling of 531540656561 in words is "five hundred thirty-one billion, five hundred forty million, six hundred fifty-six thousand, five hundred sixty-one".