857221087 has 4 divisors (see below), whose sum is σ = 857387160. Its totient is φ = 857055016.

The previous prime is 857221067. The next prime is 857221093. The reversal of 857221087 is 780122758.

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

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-857221087 is a prime.

It is a Smith number, since the sum of its digits (40) coincides with the sum of the digits of its prime factors. Since it is squarefree, it is also a hoax number.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (857221007) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 75037 + ... + 85702.

It is an arithmetic number, because the mean of its divisors is an integer number (214346790).

Almost surely, 2^857221087 is an apocalyptic number.

857221087 is a deficient number, since it is larger than the sum of its proper divisors (166073).

857221087 is a wasteful number, since it uses less digits than its factorization.

857221087 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 166072.

The product of its (nonzero) digits is 62720, while the sum is 40.

The square root of 857221087 is about 29278.3381871308. The cubic root of 857221087 is about 949.9431496913.

The spelling of 857221087 in words is "eight hundred fifty-seven million, two hundred twenty-one thousand, eighty-seven".