11915501621 has 4 divisors (see below), whose sum is σ = 12020948652. Its totient is φ = 11810054592.

The previous prime is 11915501593. The next prime is 11915501623. The reversal of 11915501621 is 12610551911.

It is a happy number.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 12610551911 = 1931 ⋅6530581.

It can be written as a sum of positive squares in 2 ways, for example, as 5465644900 + 6449856721 = 73930^2 + 80311^2 .

It is a cyclic number.

It is not a de Polignac number, because 11915501621 - 2⁶ = 11915501557 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 (11915501623) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 52723346 + ... + 52723571.

It is an arithmetic number, because the mean of its divisors is an integer number (3005237163).

Almost surely, 2^11915501621 is an apocalyptic number.

It is an amenable number.

11915501621 is a deficient number, since it is larger than the sum of its proper divisors (105447031).

11915501621 is a wasteful number, since it uses less digits than its factorization.

11915501621 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 105447030.

The product of its (nonzero) digits is 2700, while the sum is 32.

The spelling of 11915501621 in words is "eleven billion, nine hundred fifteen million, five hundred one thousand, six hundred twenty-one".