123898409 has 2 divisors, whose sum is σ = 123898410. Its totient is φ = 123898408.

The previous prime is 123898399. The next prime is 123898429. The reversal of 123898409 is 904898321.

It is a happy number.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 119683600 + 4214809 = 10940^2 + 2053^2 .

It is a cyclic number.

It is not a de Polignac number, because 123898409 - 2²⁰ = 122849833 is a prime.

It is a Sophie Germain prime.

It is a Curzon number.

It is a self number, because there is not a number n which added to its sum of digits gives 123898409.

It is not a weakly prime, because it can be changed into another prime (123898429) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 61949204 + 61949205.

It is an arithmetic number, because the mean of its divisors is an integer number (61949205).

Almost surely, 2^123898409 is an apocalyptic number.

It is an amenable number.

123898409 is a deficient number, since it is larger than the sum of its proper divisors (1).

123898409 is an equidigital number, since it uses as much as digits as its factorization.

123898409 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 124416, while the sum is 44.

The square root of 123898409 is about 11130.9662204141. The cubic root of 123898409 is about 498.5268760742.

The spelling of 123898409 in words is "one hundred twenty-three million, eight hundred ninety-eight thousand, four hundred nine".