261893725067521 has 4 divisors (see below), whose sum is σ = 261896331516592. Its totient is φ = 261891118618452.

The previous prime is 261893725067519. The next prime is 261893725067629. The reversal of 261893725067521 is 125760527398162.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is a cyclic number.

It is not a de Polignac number, because 261893725067521 - 2¹ = 261893725067519 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (261893725062521) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 1303073811 + ... + 1303274776.

It is an arithmetic number, because the mean of its divisors is an integer number (65474082879148).

Almost surely, 2^{261893725067521} is an apocalyptic number.

It is an amenable number.

261893725067521 is a deficient number, since it is larger than the sum of its proper divisors (2606449071).

261893725067521 is a wasteful number, since it uses less digits than its factorization.

261893725067521 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2606449070.

The product of its (nonzero) digits is 76204800, while the sum is 64.

The spelling of 261893725067521 in words is "two hundred sixty-one trillion, eight hundred ninety-three billion, seven hundred twenty-five million, sixty-seven thousand, five hundred twenty-one".