261421726515011 has 4 divisors (see below), whose sum is σ = 261423949247400. Its totient is φ = 261419503782624.

The previous prime is 261421726515007. The next prime is 261421726515013. The reversal of 261421726515011 is 110515627124162.

It is a semiprime because it is the product of two primes.

It is a cyclic number.

It is not a de Polignac number, because 261421726515011 - 2² = 261421726515007 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (261421726515013) 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, 1111189766 + ... + 1111425003.

It is an arithmetic number, because the mean of its divisors is an integer number (65355987311850).

Almost surely, 2^{261421726515011} is an apocalyptic number.

261421726515011 is a deficient number, since it is larger than the sum of its proper divisors (2222732389).

261421726515011 is a wasteful number, since it uses less digits than its factorization.

261421726515011 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2222732388.

The product of its (nonzero) digits is 201600, while the sum is 44.

The spelling of 261421726515011 in words is "two hundred sixty-one trillion, four hundred twenty-one billion, seven hundred twenty-six million, five hundred fifteen thousand, eleven".