651320221 has 2 divisors, whose sum is σ = 651320222. Its totient is φ = 651320220.

The previous prime is 651320149. The next prime is 651320311. The reversal of 651320221 is 122023156.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 390852900 + 260467321 = 19770^2 + 16139^2 .

It is a cyclic number.

It is not a de Polignac number, because 651320221 - 2⁹ = 651319709 is a prime.

It is a junction number, because it is equal to n+sod(n) for n = 651320192 and 651320201.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (651320921) 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 as a sum of consecutive naturals, namely, 325660110 + 325660111.

It is an arithmetic number, because the mean of its divisors is an integer number (325660111).

Almost surely, 2^651320221 is an apocalyptic number.

It is an amenable number.

651320221 is a deficient number, since it is larger than the sum of its proper divisors (1).

651320221 is an equidigital number, since it uses as much as digits as its factorization.

651320221 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 720, while the sum is 22.

The square root of 651320221 is about 25520.9760981041. The cubic root of 651320221 is about 866.8251841374.

Adding to 651320221 its reverse (122023156), we get a palindrome (773343377).

The spelling of 651320221 in words is "six hundred fifty-one million, three hundred twenty thousand, two hundred twenty-one".