1394789821 has 2 divisors, whose sum is σ = 1394789822. Its totient is φ = 1394789820.

The previous prime is 1394789807. The next prime is 1394789831. The reversal of 1394789821 is 1289874931.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 766736100 + 628053721 = 27690^2 + 25061^2 .

It is an emirp because it is prime and its reverse (1289874931) is a distict prime.

It is a cyclic number.

It is not a de Polignac number, because 1394789821 - 2¹¹ = 1394787773 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (1394789831) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 697394910 + 697394911.

It is an arithmetic number, because the mean of its divisors is an integer number (697394911).

Almost surely, 2^1394789821 is an apocalyptic number.

It is an amenable number.

1394789821 is a deficient number, since it is larger than the sum of its proper divisors (1).

1394789821 is an equidigital number, since it uses as much as digits as its factorization.

1394789821 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 870912, while the sum is 52.

The square root of 1394789821 is about 37346.8850240552. The cubic root of 1394789821 is about 1117.2994623028.

The spelling of 1394789821 in words is "one billion, three hundred ninety-four million, seven hundred eighty-nine thousand, eight hundred twenty-one".