825851721 has 32 divisors (see below), whose sum is σ = 1181952000. Its totient is φ = 511109120.

The previous prime is 825851717. The next prime is 825851753. The reversal of 825851721 is 127158528.

It is a cyclic number.

It is not a de Polignac number, because 825851721 - 2² = 825851717 is a prime.

It is a self number, because there is not a number n which added to its sum of digits gives 825851721.

It is not an unprimeable number, because it can be changed into a prime (825851771) 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 31 ways as a sum of consecutive naturals, for example, 1451125 + ... + 1451693.

It is an arithmetic number, because the mean of its divisors is an integer number (36936000).

Almost surely, 2^825851721 is an apocalyptic number.

It is an amenable number.

825851721 is a deficient number, since it is larger than the sum of its proper divisors (356100279).

825851721 is a wasteful number, since it uses less digits than its factorization.

825851721 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 929.

The product of its digits is 44800, while the sum is 39.

The square root of 825851721 is about 28737.6359674904. The cubic root of 825851721 is about 938.2113720411.

The spelling of 825851721 in words is "eight hundred twenty-five million, eight hundred fifty-one thousand, seven hundred twenty-one".