11655577521 has 81 divisors (see below), whose sum is σ = 20168938881. Its totient is φ = 6467295744.

The previous prime is 11655577513. The next prime is 11655577529. The reversal of 11655577521 is 12577555611.

The square root of 11655577521 is 107961.

It is a perfect power (a square), and thus also a powerful number.

11655577521 is a `hidden beast` number, since 1 + 1 + 6 + 5 + 55 + 77 + 521 = 666.

It is an interprime number because it is at equal distance from previous prime (11655577513) and next prime (11655577529).

It can be written as a sum of positive squares in 4 ways, for example, as 364389921 + 11291187600 = 19089^2 + 106260^2 .

It is not a de Polignac number, because 11655577521 - 2³ = 11655577513 is a prime.

It is not an unprimeable number, because it can be changed into a prime (11655577529) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (23) of ones.

It is a polite number, since it can be written in 80 ways as a sum of consecutive naturals, for example, 120160545 + ... + 120160641.

Almost surely, 2^11655577521 is an apocalyptic number.

11655577521 is the 107961-st square number.

11655577521 is the 53981-st centered octagonal number.

It is an amenable number.

11655577521 is a deficient number, since it is larger than the sum of its proper divisors (8513361360).

11655577521 is an frugal number, since it uses more digits than its factorization.

11655577521 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 320 (or 160 counting only the distinct ones).

The product of its digits is 367500, while the sum is 45.

The spelling of 11655577521 in words is "eleven billion, six hundred fifty-five million, five hundred seventy-seven thousand, five hundred twenty-one".