123740509 has 2 divisors, whose sum is σ = 123740510. Its totient is φ = 123740508.

The previous prime is 123740473. The next prime is 123740579. The reversal of 123740509 is 905047321.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 69305625 + 54434884 = 8325^2 + 7378^2 .

It is a cyclic number.

It is not a de Polignac number, because 123740509 - 2⁷ = 123740381 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (123740579) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 61870254 + 61870255.

It is an arithmetic number, because the mean of its divisors is an integer number (61870255).

Almost surely, 2^123740509 is an apocalyptic number.

It is an amenable number.

123740509 is a deficient number, since it is larger than the sum of its proper divisors (1).

123740509 is an equidigital number, since it uses as much as digits as its factorization.

123740509 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 7560, while the sum is 31.

The square root of 123740509 is about 11123.8711337376. The cubic root of 123740509 is about 498.3150066401.

The spelling of 123740509 in words is "one hundred twenty-three million, seven hundred forty thousand, five hundred nine".