20941428557 has 18 divisors (see below), whose sum is σ = 24427937898. Its totient is φ = 17900154048.

The previous prime is 20941428511. The next prime is 20941428587. The reversal of 20941428557 is 75582414902.

It can be written as a sum of positive squares in 3 ways, for example, as 8355056836 + 12586371721 = 91406^2 + 112189^2 .

It is not a de Polignac number, because 20941428557 - 2²⁰ = 20940379981 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (20941428587) 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 17 ways as a sum of consecutive naturals, for example, 25885169 + ... + 25885977.

It is an arithmetic number, because the mean of its divisors is an integer number (1357107661).

Almost surely, 2^20941428557 is an apocalyptic number.

It is an amenable number.

20941428557 is a deficient number, since it is larger than the sum of its proper divisors (3486509341).

20941428557 is an frugal number, since it uses more digits than its factorization.

20941428557 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2285 (or 1469 counting only the distinct ones).

The product of its (nonzero) digits is 806400, while the sum is 47.

The spelling of 20941428557 in words is "twenty billion, nine hundred forty-one million, four hundred twenty-eight thousand, five hundred fifty-seven".