261533540264555 has 16 divisors (see below), whose sum is σ = 357863088580704. Its totient is φ = 181771727531520.

The previous prime is 261533540264509. The next prime is 261533540264603. The reversal of 261533540264555 is 555462045335162.

It is not a de Polignac number, because 261533540264555 - 2¹⁸ = 261533540002411 is a prime.

It is a super-2 number, since 2×261533540264555² (a number of 30 digits) contains 22 as substring.

It is a self number, because there is not a number n which added to its sum of digits gives 261533540264555.

It is an unprimeable number.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 118340967341 + ... + 118340969550.

It is an arithmetic number, because the mean of its divisors is an integer number (22366443036294).

Almost surely, 2^{261533540264555} is an apocalyptic number.

261533540264555 is a deficient number, since it is larger than the sum of its proper divisors (96329548316149).

261533540264555 is a wasteful number, since it uses less digits than its factorization.

261533540264555 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 236681936926.

The product of its (nonzero) digits is 64800000, while the sum is 56.

The spelling of 261533540264555 in words is "two hundred sixty-one trillion, five hundred thirty-three billion, five hundred forty million, two hundred sixty-four thousand, five hundred fifty-five".