21115665620241 has 4 divisors (see below), whose sum is σ = 28154220826992. Its totient is φ = 14077110413492.

The previous prime is 21115665620227. The next prime is 21115665620303. The reversal of 21115665620241 is 14202656651112.

It is a happy number.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is a cyclic number.

It is not a de Polignac number, because 21115665620241 - 2¹¹ = 21115665618193 is a prime.

It is a junction number, because it is equal to n+sod(n) for n = 21115665620193 and 21115665620202.

It is not an unprimeable number, because it can be changed into a prime (21115665220241) 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, 3519277603371 + ... + 3519277603376.

It is an arithmetic number, because the mean of its divisors is an integer number (7038555206748).

Almost surely, 2^{21115665620241} is an apocalyptic number.

It is an amenable number.

21115665620241 is a deficient number, since it is larger than the sum of its proper divisors (7038555206751).

21115665620241 is an equidigital number, since it uses as much as digits as its factorization.

21115665620241 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 7038555206750.

The product of its (nonzero) digits is 172800, while the sum is 42.

The spelling of 21115665620241 in words is "twenty-one trillion, one hundred fifteen billion, six hundred sixty-five million, six hundred twenty thousand, two hundred forty-one".