823578309949 has 2 divisors, whose sum is σ = 823578309950. Its totient is φ = 823578309948.

The previous prime is 823578309937. The next prime is 823578310019. The reversal of 823578309949 is 949903875328.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 417694641849 + 405883668100 = 646293^2 + 637090^2 .

It is a cyclic number.

It is not a de Polignac number, because 823578309949 - 2⁷ = 823578309821 is a prime.

It is a super-2 number, since 2×823578309949² (a number of 25 digits) contains 22 as substring.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (823578309919) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 411789154974 + 411789154975.

It is an arithmetic number, because the mean of its divisors is an integer number (411789154975).

Almost surely, 2^823578309949 is an apocalyptic number.

It is an amenable number.

823578309949 is a deficient number, since it is larger than the sum of its proper divisors (1).

823578309949 is an equidigital number, since it uses as much as digits as its factorization.

823578309949 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 117573120, while the sum is 67.

The spelling of 823578309949 in words is "eight hundred twenty-three billion, five hundred seventy-eight million, three hundred nine thousand, nine hundred forty-nine".