857221517 has 16 divisors (see below), whose sum is σ = 907026432. Its totient is φ = 809051760.

The previous prime is 857221511. The next prime is 857221543. The reversal of 857221517 is 715122758.

It is a cyclic number.

It is not a de Polignac number, because 857221517 - 2¹⁰ = 857220493 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 (857221511) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 211928 + ... + 215934.

It is an arithmetic number, because the mean of its divisors is an integer number (56689152).

Almost surely, 2^857221517 is an apocalyptic number.

It is an amenable number.

857221517 is a deficient number, since it is larger than the sum of its proper divisors (49804915).

857221517 is a wasteful number, since it uses less digits than its factorization.

857221517 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 4208.

The product of its digits is 39200, while the sum is 38.

The square root of 857221517 is about 29278.3455304428. The cubic root of 857221517 is about 949.9433085283.

The spelling of 857221517 in words is "eight hundred fifty-seven million, two hundred twenty-one thousand, five hundred seventeen".