261533605664271 has 32 divisors (see below), whose sum is σ = 368074298199040. Its totient is φ = 164724827589504.

The previous prime is 261533605664159. The next prime is 261533605664273. The reversal of 261533605664271 is 172466506335162.

It is not a de Polignac number, because 261533605664271 - 2¹⁵ = 261533605631503 is a prime.

It is a super-2 number, since 2×261533605664271² (a number of 30 digits) contains 22 as substring.

It is a Harshad number since it is a multiple of its sum of digits (57).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (261533605664273) by changing a digit.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 954041301 + ... + 954315393.

It is an arithmetic number, because the mean of its divisors is an integer number (11502321818720).

Almost surely, 2^{261533605664271} is an apocalyptic number.

261533605664271 is a deficient number, since it is larger than the sum of its proper divisors (106540692534769).

261533605664271 is a wasteful number, since it uses less digits than its factorization.

261533605664271 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 320095.

The product of its (nonzero) digits is 32659200, while the sum is 57.

The spelling of 261533605664271 in words is "two hundred sixty-one trillion, five hundred thirty-three billion, six hundred five million, six hundred sixty-four thousand, two hundred seventy-one".