857666115565 has 16 divisors (see below), whose sum is σ = 1176292212480. Its totient is φ = 588081709440.

The previous prime is 857666115547. The next prime is 857666115571. The reversal of 857666115565 is 565511666758.

It is not a de Polignac number, because 857666115565 - 2¹³ = 857666107373 is a prime.

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (23) of ones.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 13305 + ... + 1309774.

It is an arithmetic number, because the mean of its divisors is an integer number (73518263280).

Almost surely, 2^857666115565 is an apocalyptic number.

It is an amenable number.

857666115565 is a deficient number, since it is larger than the sum of its proper divisors (318626096915).

857666115565 is a wasteful number, since it uses less digits than its factorization.

857666115565 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1341612.

The product of its digits is 45360000, while the sum is 61.

The spelling of 857666115565 in words is "eight hundred fifty-seven billion, six hundred sixty-six million, one hundred fifteen thousand, five hundred sixty-five".