2001078656789 has 2 divisors, whose sum is σ = 2001078656790. Its totient is φ = 2001078656788.

The previous prime is 2001078656771. The next prime is 2001078656821. The reversal of 2001078656789 is 9876568701002.

It is a happy number.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 1992007618225 + 9071038564 = 1411385^2 + 95242^2 .

It is a cyclic number.

It is not a de Polignac number, because 2001078656789 - 2¹² = 2001078652693 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (2001078656749) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 1000539328394 + 1000539328395.

It is an arithmetic number, because the mean of its divisors is an integer number (1000539328395).

Almost surely, 2^{2001078656789} is an apocalyptic number.

It is an amenable number.

2001078656789 is a deficient number, since it is larger than the sum of its proper divisors (1).

2001078656789 is an equidigital number, since it uses as much as digits as its factorization.

2001078656789 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 10160640, while the sum is 59.

The spelling of 2001078656789 in words is "two trillion, one billion, seventy-eight million, six hundred fifty-six thousand, seven hundred eighty-nine".