20542442021 has 4 divisors (see below), whose sum is σ = 21623623200. Its totient is φ = 19461260844.

The previous prime is 20542442003. The next prime is 20542442087. The reversal of 20542442021 is 12024424502.

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 20542442021 - 2²⁶ = 20475333157 is a prime.

It is a super-2 number, since 2×20542442021² (a number of 21 digits) contains 22 as substring.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (20542447021) 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, 540590561 + ... + 540590598.

It is an arithmetic number, because the mean of its divisors is an integer number (5405905800).

Almost surely, 2^20542442021 is an apocalyptic number.

It is an amenable number.

20542442021 is a deficient number, since it is larger than the sum of its proper divisors (1081181179).

20542442021 is a wasteful number, since it uses less digits than its factorization.

20542442021 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1081181178.

The product of its (nonzero) digits is 5120, while the sum is 26.

Adding to 20542442021 its reverse (12024424502), we get a palindrome (32566866523).

The spelling of 20542442021 in words is "twenty billion, five hundred forty-two million, four hundred forty-two thousand, twenty-one".