1391690789 has 2 divisors, whose sum is σ = 1391690790. Its totient is φ = 1391690788.

The previous prime is 1391690747. The next prime is 1391690813. The reversal of 1391690789 is 9870961931.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 1026689764 + 365001025 = 32042^2 + 19105^2 .

It is a cyclic number.

It is not a de Polignac number, because 1391690789 - 2¹² = 1391686693 is a prime.

It is a self number, because there is not a number n which added to its sum of digits gives 1391690789.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (1391690089) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 695845394 + 695845395.

It is an arithmetic number, because the mean of its divisors is an integer number (695845395).

Almost surely, 2^1391690789 is an apocalyptic number.

It is an amenable number.

1391690789 is a deficient number, since it is larger than the sum of its proper divisors (1).

1391690789 is an equidigital number, since it uses as much as digits as its factorization.

1391690789 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 734832, while the sum is 53.

The square root of 1391690789 is about 37305.3721198435. The cubic root of 1391690789 is about 1116.4713532118.

The spelling of 1391690789 in words is "one billion, three hundred ninety-one million, six hundred ninety thousand, seven hundred eighty-nine".