20505442154 has 8 divisors (see below), whose sum is σ = 30759419460. Its totient is φ = 10252302336.

The previous prime is 20505442127. The next prime is 20505442157. The reversal of 20505442154 is 45124450502.

It can be written as a sum of positive squares in 2 ways, for example, as 19820416225 + 685025929 = 140785^2 + 26173^2 .

It is a sphenic number, since it is the product of 3 distinct primes.

It is a Curzon number.

It is a self number, because there is not a number n which added to its sum of digits gives 20505442154.

It is not an unprimeable number, because it can be changed into a prime (20505442157) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 144089 + ... + 248540.

Almost surely, 2^20505442154 is an apocalyptic number.

20505442154 is a deficient number, since it is larger than the sum of its proper divisors (10253977306).

20505442154 is a wasteful number, since it uses less digits than its factorization.

20505442154 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 418744.

The product of its (nonzero) digits is 32000, while the sum is 32.

Adding to 20505442154 its reverse (45124450502), we get a palindrome (65629892656).

The spelling of 20505442154 in words is "twenty billion, five hundred five million, four hundred forty-two thousand, one hundred fifty-four".