823990789 has 2 divisors, whose sum is σ = 823990790. Its totient is φ = 823990788.

The previous prime is 823990787. The next prime is 823990823. The reversal of 823990789 is 987099328.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 813960900 + 10029889 = 28530^2 + 3167^2 .

It is a cyclic number.

It is not a de Polignac number, because 823990789 - 2¹ = 823990787 is a prime.

Together with 823990787, it forms a pair of twin primes.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (823990781) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 411995394 + 411995395.

It is an arithmetic number, because the mean of its divisors is an integer number (411995395).

Almost surely, 2^823990789 is an apocalyptic number.

It is an amenable number.

823990789 is a deficient number, since it is larger than the sum of its proper divisors (1).

823990789 is an equidigital number, since it uses as much as digits as its factorization.

823990789 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 1959552, while the sum is 55.

The square root of 823990789 is about 28705.2397481714. The cubic root of 823990789 is about 937.5061362324.

The spelling of 823990789 in words is "eight hundred twenty-three million, nine hundred ninety thousand, seven hundred eighty-nine".