261534263432521 has 4 divisors (see below), whose sum is σ = 261627568559632. Its totient is φ = 261440958305412.

The previous prime is 261534263432467. The next prime is 261534263432543. The reversal of 261534263432521 is 125234362435162.

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 261534263432521 - 2²⁷ = 261534129214793 is a prime.

It is a super-2 number, since 2×261534263432521² (a number of 30 digits) contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (261534263432551) 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, 46652559351 + ... + 46652564956.

It is an arithmetic number, because the mean of its divisors is an integer number (65406892139908).

Almost surely, 2^{261534263432521} is an apocalyptic number.

It is an amenable number.

261534263432521 is a deficient number, since it is larger than the sum of its proper divisors (93305127111).

261534263432521 is an equidigital number, since it uses as much as digits as its factorization.

261534263432521 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 93305127110.

The product of its digits is 6220800, while the sum is 49.

The spelling of 261534263432521 in words is "two hundred sixty-one trillion, five hundred thirty-four billion, two hundred sixty-three million, four hundred thirty-two thousand, five hundred twenty-one".