21120211530541 has 4 divisors (see below), whose sum is σ = 21635338641084. Its totient is φ = 20605084420000.

The previous prime is 21120211530529. The next prime is 21120211530599. The reversal of 21120211530541 is 14503511202112.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 1303878515625 + 19816333014916 = 1141875^2 + 4451554^2 .

It is a cyclic number.

It is not a de Polignac number, because 21120211530541 - 2¹⁵ = 21120211497773 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 (21120211530521) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 257563555210 + ... + 257563555291.

It is an arithmetic number, because the mean of its divisors is an integer number (5408834660271).

Almost surely, 2^{21120211530541} is an apocalyptic number.

It is an amenable number.

21120211530541 is a deficient number, since it is larger than the sum of its proper divisors (515127110543).

21120211530541 is an equidigital number, since it uses as much as digits as its factorization.

21120211530541 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 515127110542.

The product of its (nonzero) digits is 2400, while the sum is 28.

Adding to 21120211530541 its reverse (14503511202112), we get a palindrome (35623722732653).

The spelling of 21120211530541 in words is "twenty-one trillion, one hundred twenty billion, two hundred eleven million, five hundred thirty thousand, five hundred forty-one".