57121653821 has 4 divisors (see below), whose sum is σ = 57122132700. Its totient is φ = 57121174944.

The previous prime is 57121653817. The next prime is 57121653847. The reversal of 57121653821 is 12835612175.

It is a happy number.

It is a semiprime because it is the product of two primes, and also a brilliant number, because the two primes have the same length.

It can be written as a sum of positive squares in 2 ways, for example, as 40074434596 + 17047219225 = 200186^2 + 130565^2 .

It is a cyclic number.

It is not a de Polignac number, because 57121653821 - 2² = 57121653817 is a prime.

It is a Duffinian number.

It is a Curzon number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (57121653221) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 98015 + ... + 351923.

It is an arithmetic number, because the mean of its divisors is an integer number (14280533175).

Almost surely, 2^57121653821 is an apocalyptic number.

It is an amenable number.

57121653821 is a deficient number, since it is larger than the sum of its proper divisors (478879).

57121653821 is a wasteful number, since it uses less digits than its factorization.

57121653821 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 478878.

The product of its digits is 100800, while the sum is 41.

The spelling of 57121653821 in words is "fifty-seven billion, one hundred twenty-one million, six hundred fifty-three thousand, eight hundred twenty-one".