857925121565 has 16 divisors (see below), whose sum is σ = 1058723794800. Its totient is φ = 666994606080.

The previous prime is 857925121531. The next prime is 857925121609. The reversal of 857925121565 is 565121529758.

It can be written as a sum of positive squares in 8 ways, for example, as 350962756 + 857574158809 = 18734^2 + 926053^2 .

It is not a de Polignac number, because 857925121565 - 2¹⁴ = 857925105181 is a prime.

It is a self number, because there is not a number n which added to its sum of digits gives 857925121565.

It is a congruent number.

It is an unprimeable number.

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 15 ways as a sum of consecutive naturals, for example, 8089340 + ... + 8194709.

It is an arithmetic number, because the mean of its divisors is an integer number (66170237175).

Almost surely, 2^857925121565 is an apocalyptic number.

It is an amenable number.

857925121565 is a deficient number, since it is larger than the sum of its proper divisors (200798673235).

857925121565 is a wasteful number, since it uses less digits than its factorization.

857925121565 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 16284352.

The product of its digits is 7560000, while the sum is 56.

The spelling of 857925121565 in words is "eight hundred fifty-seven billion, nine hundred twenty-five million, one hundred twenty-one thousand, five hundred sixty-five".