718138409 has 2 divisors, whose sum is σ = 718138410. Its totient is φ = 718138408.

The previous prime is 718138373. The next prime is 718138423. The reversal of 718138409 is 904831817.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 385258384 + 332880025 = 19628^2 + 18245^2 .

It is a cyclic number.

It is not a de Polignac number, because 718138409 - 2⁸ = 718138153 is a prime.

It is a Sophie Germain prime.

It is a Chen prime.

It is a Curzon number.

It is equal to p_37142897 and since 718138409 and 37142897 have the same sum of digits, it is a Honaker prime.

It is not a weakly prime, because it can be changed into another prime (718138489) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 359069204 + 359069205.

It is an arithmetic number, because the mean of its divisors is an integer number (359069205).

Almost surely, 2^718138409 is an apocalyptic number.

It is an amenable number.

718138409 is a deficient number, since it is larger than the sum of its proper divisors (1).

718138409 is an equidigital number, since it uses as much as digits as its factorization.

718138409 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 48384, while the sum is 41.

The square root of 718138409 is about 26798.1045784958. The cubic root of 718138409 is about 895.5078249512.

The spelling of 718138409 in words is "seven hundred eighteen million, one hundred thirty-eight thousand, four hundred nine".