857221656 has 32 divisors (see below), whose sum is σ = 2167138800. Its totient is φ = 282529280.

The previous prime is 857221637. The next prime is 857221657. The reversal of 857221656 is 656122758.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (857221657) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 198525 + ... + 202796.

Almost surely, 2^857221656 is an apocalyptic number.

It is an amenable number.

857221656 is an abundant number, since it is smaller than the sum of its proper divisors (1309917144).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

857221656 is a wasteful number, since it uses less digits than its factorization.

857221656 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 401419 (or 401415 counting only the distinct ones).

The product of its digits is 201600, while the sum is 42.

The square root of 857221656 is about 29278.3479042107. The cubic root of 857221656 is about 949.9433598733.

It can be divided in two parts, 85722 and 1656, that added together give a palindrome (87378).

The spelling of 857221656 in words is "eight hundred fifty-seven million, two hundred twenty-one thousand, six hundred fifty-six".