857000721 has 8 divisors (see below), whose sum is σ = 1182070080. Its totient is φ = 551632592.

The previous prime is 857000717. The next prime is 857000741. The reversal of 857000721 is 127000758.

It is a happy number.

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 857000721 - 2² = 857000717 is a prime.

It is not an unprimeable number, because it can be changed into a prime (857000741) 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 7 ways as a sum of consecutive naturals, for example, 4925205 + ... + 4925378.

It is an arithmetic number, because the mean of its divisors is an integer number (147758760).

Almost surely, 2^857000721 is an apocalyptic number.

It is an amenable number.

857000721 is a deficient number, since it is larger than the sum of its proper divisors (325069359).

857000721 is a wasteful number, since it uses less digits than its factorization.

857000721 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 9850615.

The product of its (nonzero) digits is 3920, while the sum is 30.

The square root of 857000721 is about 29274.5746510517. The cubic root of 857000721 is about 949.8617420218.

The spelling of 857000721 in words is "eight hundred fifty-seven million, seven hundred twenty-one", and thus it is an aban number.