21615543222445 has 4 divisors (see below), whose sum is σ = 25938651866940. Its totient is φ = 17292434577952.

The previous prime is 21615543222433. The next prime is 21615543222479. The reversal of 21615543222445 is 54422234551612.

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 14596418916676 + 7019124305769 = 3820526^2 + 2649363^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-21615543222445 is a prime.

It is a junction number, because it is equal to n+sod(n) for n = 21615543222395 and 21615543222404.

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 2161554322240 + ... + 2161554322249.

It is an arithmetic number, because the mean of its divisors is an integer number (6484662966735).

Almost surely, 2^{21615543222445} is an apocalyptic number.

It is an amenable number.

21615543222445 is a deficient number, since it is larger than the sum of its proper divisors (4323108644495).

21615543222445 is an equidigital number, since it uses as much as digits as its factorization.

21615543222445 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 4323108644494.

The product of its digits is 2304000, while the sum is 46.

The spelling of 21615543222445 in words is "twenty-one trillion, six hundred fifteen billion, five hundred forty-three million, two hundred twenty-two thousand, four hundred forty-five".