123816409 has 2 divisors, whose sum is σ = 123816410. Its totient is φ = 123816408.

The previous prime is 123816391. The next prime is 123816419. The reversal of 123816409 is 904618321.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 68641225 + 55175184 = 8285^2 + 7428^2 .

It is an emirp because it is prime and its reverse (904618321) is a distict prime.

It is a cyclic number.

It is not a de Polignac number, because 123816409 - 2⁷ = 123816281 is a prime.

It is not a weakly prime, because it can be changed into another prime (123816419) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 61908204 + 61908205.

It is an arithmetic number, because the mean of its divisors is an integer number (61908205).

Almost surely, 2^123816409 is an apocalyptic number.

It is an amenable number.

123816409 is a deficient number, since it is larger than the sum of its proper divisors (1).

123816409 is an equidigital number, since it uses as much as digits as its factorization.

123816409 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 10368, while the sum is 34.

The square root of 123816409 is about 11127.2821928807. The cubic root of 123816409 is about 498.4168713645.

The spelling of 123816409 in words is "one hundred twenty-three million, eight hundred sixteen thousand, four hundred nine".