11551236461521 has 9 divisors (see below), whose sum is σ = 11802399832731. Its totient is φ = 11305309132272.

The previous prime is 11551236461491. The next prime is 11551236461551. The reversal of 11551236461521 is 12516463215511.

The square root of 11551236461521 is 3398711.

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

It is an interprime number because it is at equal distance from previous prime (11551236461491) and next prime (11551236461551).

It can be written as a sum of positive squares in only one way, i.e., 10906209027025 + 645027434496 = 3302455^2 + 803136^2 .

It is not a de Polignac number, because 11551236461521 - 2⁴¹ = 9352213205969 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (11551236461551) by changing a digit.

It is a polite number, since it can be written in 8 ways as a sum of consecutive naturals, for example, 159703261 + ... + 159775573.

Almost surely, 2^{11551236461521} is an apocalyptic number.

11551236461521 is the 3398711-st square number.

11551236461521 is the 1699356-th centered octagonal number.

It is an amenable number.

11551236461521 is a deficient number, since it is larger than the sum of its proper divisors (251163371210).

11551236461521 is an frugal number, since it uses more digits than its factorization.

11551236461521 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 144720 (or 72360 counting only the distinct ones).

The product of its digits is 216000, while the sum is 43.

The spelling of 11551236461521 in words is "eleven trillion, five hundred fifty-one billion, two hundred thirty-six million, four hundred sixty-one thousand, five hundred twenty-one".