11205572661 has 24 divisors (see below), whose sum is σ = 17143340760. Its totient is φ = 7028729856.

The previous prime is 11205572641. The next prime is 11205572669. The reversal of 11205572661 is 16627550211.

11205572661 is a `hidden beast` number, since 1 + 1 + 20 + 5 + 572 + 6 + 61 = 666.

It can be written as a sum of positive squares in 4 ways, for example, as 299947761 + 10905624900 = 17319^2 + 104430^2 .

It is not a de Polignac number, because 11205572661 - 2⁶ = 11205572597 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (11205572669) by changing a digit.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 570675 + ... + 589983.

It is an arithmetic number, because the mean of its divisors is an integer number (714305865).

Almost surely, 2^11205572661 is an apocalyptic number.

It is an amenable number.

11205572661 is a deficient number, since it is larger than the sum of its proper divisors (5937768099).

11205572661 is a wasteful number, since it uses less digits than its factorization.

11205572661 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 23125 (or 23122 counting only the distinct ones).

The product of its (nonzero) digits is 25200, while the sum is 36.

The spelling of 11205572661 in words is "eleven billion, two hundred five million, five hundred seventy-two thousand, six hundred sixty-one".