8357721 has 4 divisors (see below), whose sum is σ = 11143632. Its totient is φ = 5571812.

The previous prime is 8357719. The next prime is 8357731. The reversal of 8357721 is 1277538.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is a cyclic number.

It is not a de Polignac number, because 8357721 - 2¹ = 8357719 is a prime.

It is a Curzon number.

It is not an unprimeable number, because it can be changed into a prime (8357711) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 1392951 + ... + 1392956.

It is an arithmetic number, because the mean of its divisors is an integer number (2785908).

Almost surely, 2^8357721 is an apocalyptic number.

It is an amenable number.

8357721 is a deficient number, since it is larger than the sum of its proper divisors (2785911).

8357721 is a wasteful number, since it uses less digits than its factorization.

8357721 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2785910.

The product of its digits is 11760, while the sum is 33.

The square root of 8357721 is about 2890.9723277818. The cubic root of 8357721 is about 202.9376481885.

The spelling of 8357721 in words is "eight million, three hundred fifty-seven thousand, seven hundred twenty-one".