651006661 has 2 divisors, whose sum is σ = 651006662. Its totient is φ = 651006660.

The previous prime is 651006611. The next prime is 651006677. The reversal of 651006661 is 166600156.

651006661 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 446688225 + 204318436 = 21135^2 + 14294^2 .

It is a cyclic number.

It is not a de Polignac number, because 651006661 - 2²¹ = 648909509 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (651006611) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 325503330 + 325503331.

It is an arithmetic number, because the mean of its divisors is an integer number (325503331).

Almost surely, 2^651006661 is an apocalyptic number.

It is an amenable number.

651006661 is a deficient number, since it is larger than the sum of its proper divisors (1).

651006661 is an equidigital number, since it uses as much as digits as its factorization.

651006661 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 6480, while the sum is 31.

The square root of 651006661 is about 25514.8321765988. The cubic root of 651006661 is about 866.6860588527.

The spelling of 651006661 in words is "six hundred fifty-one million, six thousand, six hundred sixty-one".