661000651 has 2 divisors, whose sum is σ = 661000652. Its totient is φ = 661000650.

The previous prime is 661000591. The next prime is 661000679. The reversal of 661000651 is 156000166.

661000651 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 is a cyclic number.

It is not a de Polignac number, because 661000651 - 2¹⁷ = 660869579 is a prime.

It is not a weakly prime, because it can be changed into another prime (661000051) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 330500325 + 330500326.

It is an arithmetic number, because the mean of its divisors is an integer number (330500326).

Almost surely, 2^661000651 is an apocalyptic number.

661000651 is a deficient number, since it is larger than the sum of its proper divisors (1).

661000651 is an equidigital number, since it uses as much as digits as its factorization.

661000651 is an odious number, because the sum of its binary digits is odd.

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

The square root of 661000651 is about 25709.9329248444. The cubic root of 661000651 is about 871.0985598442.

The spelling of 661000651 in words is "six hundred sixty-one million, six hundred fifty-one", and thus it is an aban number.