20421655620041 has 4 divisors (see below), whose sum is σ = 21992552206212. Its totient is φ = 18850759033872.

The previous prime is 20421655620013. The next prime is 20421655620077. The reversal of 20421655620041 is 14002655612402.

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 8952189664441 + 11469465955600 = 2992021^2 + 3386660^2 .

It is a cyclic number.

It is not a de Polignac number, because 20421655620041 - 2¹⁰ = 20421655619017 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 20421655619977 and 20421655620004.

It is not an unprimeable number, because it can be changed into a prime (20421655620001) 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, 785448293066 + ... + 785448293091.

It is an arithmetic number, because the mean of its divisors is an integer number (5498138051553).

Almost surely, 2^{20421655620041} is an apocalyptic number.

It is an amenable number.

20421655620041 is a deficient number, since it is larger than the sum of its proper divisors (1570896586171).

20421655620041 is a wasteful number, since it uses less digits than its factorization.

20421655620041 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1570896586170.

The product of its (nonzero) digits is 115200, while the sum is 38.

The spelling of 20421655620041 in words is "twenty trillion, four hundred twenty-one billion, six hundred fifty-five million, six hundred twenty thousand, forty-one".