651047921 has 2 divisors, whose sum is σ = 651047922. Its totient is φ = 651047920.

The previous prime is 651047909. The next prime is 651047951. The reversal of 651047921 is 129740156.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 645922225 + 5125696 = 25415^2 + 2264^2 .

It is a cyclic number.

It is not a de Polignac number, because 651047921 - 2⁶ = 651047857 is a prime.

It is a Sophie Germain prime.

It is a Chen prime.

It is a Curzon number.

It is not a weakly prime, because it can be changed into another prime (651047951) 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, 325523960 + 325523961.

It is an arithmetic number, because the mean of its divisors is an integer number (325523961).

Almost surely, 2^651047921 is an apocalyptic number.

It is an amenable number.

651047921 is a deficient number, since it is larger than the sum of its proper divisors (1).

651047921 is an equidigital number, since it uses as much as digits as its factorization.

651047921 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 15120, while the sum is 35.

The square root of 651047921 is about 25515.6407130999. The cubic root of 651047921 is about 866.7043682974.

The spelling of 651047921 in words is "six hundred fifty-one million, forty-seven thousand, nine hundred twenty-one".