123402509 has 2 divisors, whose sum is σ = 123402510. Its totient is φ = 123402508.

The previous prime is 123402467. The next prime is 123402529. The reversal of 123402509 is 905204321.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 107226025 + 16176484 = 10355^2 + 4022^2 .

It is a cyclic number.

It is not a de Polignac number, because 123402509 - 2¹² = 123398413 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (123402529) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 61701254 + 61701255.

It is an arithmetic number, because the mean of its divisors is an integer number (61701255).

Almost surely, 2^123402509 is an apocalyptic number.

It is an amenable number.

123402509 is a deficient number, since it is larger than the sum of its proper divisors (1).

123402509 is an equidigital number, since it uses as much as digits as its factorization.

123402509 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 2160, while the sum is 26.

The square root of 123402509 is about 11108.6681920021. The cubic root of 123402509 is about 497.8608733253.

The spelling of 123402509 in words is "one hundred twenty-three million, four hundred two thousand, five hundred nine".