20421340442045 has 4 divisors (see below), whose sum is σ = 24505608530460. Its totient is φ = 16337072353632.

The previous prime is 20421340442011. The next prime is 20421340442051. The reversal of 20421340442045 is 54024404312402.

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 4693405946329 + 15727934495716 = 2166427^2 + 3965846^2 .

It is a cyclic number.

It is not a de Polignac number, because 20421340442045 - 2⁴⁰ = 19321828814269 is a prime.

It is a super-2 number, since 2×20421340442045² (a number of 27 digits) contains 22 as substring.

It is a junction number, because it is equal to n+sod(n) for n = 20421340441996 and 20421340442014.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 2042134044200 + ... + 2042134044209.

It is an arithmetic number, because the mean of its divisors is an integer number (6126402132615).

Almost surely, 2^{20421340442045} is an apocalyptic number.

It is an amenable number.

20421340442045 is a deficient number, since it is larger than the sum of its proper divisors (4084268088415).

20421340442045 is an equidigital number, since it uses as much as digits as its factorization.

20421340442045 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 4084268088414.

The product of its (nonzero) digits is 122880, while the sum is 35.

Adding to 20421340442045 its reverse (54024404312402), we get a palindrome (74445744754447).

The spelling of 20421340442045 in words is "twenty trillion, four hundred twenty-one billion, three hundred forty million, four hundred forty-two thousand, forty-five".