20421335665144 has 32 divisors (see below), whose sum is σ = 38564635299840. Its totient is φ = 10137506796000.

The previous prime is 20421335665109. The next prime is 20421335665177. The reversal of 20421335665144 is 44156653312402.

It is a junction number, because it is equal to n+sod(n) for n = 20421335665094 and 20421335665103.

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (23) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 2404504 + ... + 6828199.

It is an arithmetic number, because the mean of its divisors is an integer number (1205144853120).

Almost surely, 2^{20421335665144} is an apocalyptic number.

It is an amenable number.

20421335665144 is a deficient number, since it is larger than the sum of its proper divisors (18143299634696).

20421335665144 is a wasteful number, since it uses less digits than its factorization.

20421335665144 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 9234691 (or 9234687 counting only the distinct ones).

The product of its (nonzero) digits is 2073600, while the sum is 46.

Adding to 20421335665144 its reverse (44156653312402), we get a palindrome (64577988977546).

The spelling of 20421335665144 in words is "twenty trillion, four hundred twenty-one billion, three hundred thirty-five million, six hundred sixty-five thousand, one hundred forty-four".