11521663645 has 8 divisors (see below), whose sum is σ = 13848408504. Its totient is φ = 9202389504.

The previous prime is 11521663633. The next prime is 11521663649. The reversal of 11521663645 is 54636612511.

It is a happy number.

It can be written as a sum of positive squares in 4 ways, for example, as 3437316 + 11518226329 = 1854^2 + 107323^2 .

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 11521663645 - 2⁹ = 11521663133 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 11521663598 and 11521663607.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (11521663649) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 1864284 + ... + 1870453.

It is an arithmetic number, because the mean of its divisors is an integer number (1731051063).

Almost surely, 2^11521663645 is an apocalyptic number.

It is an amenable number.

11521663645 is a deficient number, since it is larger than the sum of its proper divisors (2326744859).

11521663645 is an equidigital number, since it uses as much as digits as its factorization.

11521663645 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 3735359.

The product of its digits is 129600, while the sum is 40.

The spelling of 11521663645 in words is "eleven billion, five hundred twenty-one million, six hundred sixty-three thousand, six hundred forty-five".