20400054121 has 4 divisors (see below), whose sum is σ = 21473741200. Its totient is φ = 19326367044.

The previous prime is 20400054119. The next prime is 20400054127. The reversal of 20400054121 is 12145000402.

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 20400054121 - 2¹ = 20400054119 is a prime.

It is a Harshad number since it is a multiple of its sum of digits (19), and also a Moran number because the ratio is a prime number: 1073687059 = 20400054121 / (2 + 0 + 4 + 0 + 0 + 0 + 5 + 4 + 1 + 2 + 1).

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (20400054127) 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, 536843511 + ... + 536843548.

It is an arithmetic number, because the mean of its divisors is an integer number (5368435300).

Almost surely, 2^20400054121 is an apocalyptic number.

It is an amenable number.

20400054121 is a deficient number, since it is larger than the sum of its proper divisors (1073687079).

20400054121 is a wasteful number, since it uses less digits than its factorization.

20400054121 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1073687078.

The product of its (nonzero) digits is 320, while the sum is 19.

Adding to 20400054121 its reverse (12145000402), we get a palindrome (32545054523).

It can be divided in two parts, 204000 and 54121, that added together give a triangular number (258121 = T₇₁₈).

The spelling of 20400054121 in words is "twenty billion, four hundred million, fifty-four thousand, one hundred twenty-one".