821000651 has 2 divisors, whose sum is σ = 821000652. Its totient is φ = 821000650.

The previous prime is 821000641. The next prime is 821000699. The reversal of 821000651 is 156000128.

It is a weak prime.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-821000651 is a prime.

It is not a weakly prime, because it can be changed into another prime (821000641) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 410500325 + 410500326.

It is an arithmetic number, because the mean of its divisors is an integer number (410500326).

Almost surely, 2^821000651 is an apocalyptic number.

821000651 is a deficient number, since it is larger than the sum of its proper divisors (1).

821000651 is an equidigital number, since it uses as much as digits as its factorization.

821000651 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 480, while the sum is 23.

The square root of 821000651 is about 28653.1089238149. The cubic root of 821000651 is about 936.3707390501.

Adding to 821000651 its reverse (156000128), we get a palindrome (977000779).

The spelling of 821000651 in words is "eight hundred twenty-one million, six hundred fifty-one", and thus it is an aban number.