657144017021 has 4 divisors (see below), whose sum is σ = 695799547452. Its totient is φ = 618488486592.

The previous prime is 657144017003. The next prime is 657144017071. The reversal of 657144017021 is 120710441756.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 295516180996 + 361627836025 = 543614^2 + 601355^2 .

It is a cyclic number.

It is not a de Polignac number, because 657144017021 - 2¹⁸ = 657143754877 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (657144017071) 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, 19327765190 + ... + 19327765223.

It is an arithmetic number, because the mean of its divisors is an integer number (173949886863).

Almost surely, 2^657144017021 is an apocalyptic number.

It is an amenable number.

657144017021 is a deficient number, since it is larger than the sum of its proper divisors (38655530431).

657144017021 is a wasteful number, since it uses less digits than its factorization.

657144017021 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 38655530430.

The product of its (nonzero) digits is 47040, while the sum is 38.

Adding to 657144017021 its reverse (120710441756), we get a palindrome (777854458777).

The spelling of 657144017021 in words is "six hundred fifty-seven billion, one hundred forty-four million, seventeen thousand, twenty-one".