651000661 has 2 divisors, whose sum is σ = 651000662. Its totient is φ = 651000660.

The previous prime is 651000617. The next prime is 651000673. The reversal of 651000661 is 166000156.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 621504900 + 29495761 = 24930^2 + 5431^2 .

It is a cyclic number.

It is not a de Polignac number, because 651000661 - 2¹⁷ = 650869589 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (651000611) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 325500330 + 325500331.

It is an arithmetic number, because the mean of its divisors is an integer number (325500331).

Almost surely, 2^651000661 is an apocalyptic number.

It is an amenable number.

651000661 is a deficient number, since it is larger than the sum of its proper divisors (1).

651000661 is an equidigital number, since it uses as much as digits as its factorization.

651000661 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 1080, while the sum is 25.

The square root of 651000661 is about 25514.7145976591. The cubic root of 651000661 is about 866.6833962418.

The spelling of 651000661 in words is "six hundred fifty-one million, six hundred sixty-one", and thus it is an aban number.