261564324233543 has 16 divisors (see below), whose sum is σ = 266383976832000. Its totient is φ = 256757702918112.

The previous prime is 261564324233521. The next prime is 261564324233549. The reversal of 261564324233543 is 345332423465162.

It is a happy number.

It is a cyclic number.

It is not a de Polignac number, because 261564324233543 - 2¹² = 261564324229447 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (261564324233549) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 198852446 + ... + 200163492.

It is an arithmetic number, because the mean of its divisors is an integer number (16648998552000).

Almost surely, 2^{261564324233543} is an apocalyptic number.

261564324233543 is a deficient number, since it is larger than the sum of its proper divisors (4819652598457).

261564324233543 is a wasteful number, since it uses less digits than its factorization.

261564324233543 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1316014.

The product of its digits is 37324800, while the sum is 53.

The spelling of 261564324233543 in words is "two hundred sixty-one trillion, five hundred sixty-four billion, three hundred twenty-four million, two hundred thirty-three thousand, five hundred forty-three".