11515210261 has 4 divisors (see below), whose sum is σ = 11515727232. Its totient is φ = 11514693292.

The previous prime is 11515210247. The next prime is 11515210277. The reversal of 11515210261 is 16201251511.

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 11515210261 - 2²¹ = 11513113109 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (11515210211) 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, 223495 + ... + 270148.

It is an arithmetic number, because the mean of its divisors is an integer number (2878931808).

Almost surely, 2^11515210261 is an apocalyptic number.

It is an amenable number.

11515210261 is a deficient number, since it is larger than the sum of its proper divisors (516971).

11515210261 is an equidigital number, since it uses as much as digits as its factorization.

11515210261 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 516970.

The product of its (nonzero) digits is 600, while the sum is 25.

Adding to 11515210261 its reverse (16201251511), we get a palindrome (27716461772).

The spelling of 11515210261 in words is "eleven billion, five hundred fifteen million, two hundred ten thousand, two hundred sixty-one".