72440909 has 2 divisors, whose sum is σ = 72440910. Its totient is φ = 72440908.

The previous prime is 72440903. The next prime is 72440933. The reversal of 72440909 is 90904427.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 69388900 + 3052009 = 8330^2 + 1747^2 .

It is a cyclic number.

It is not a de Polignac number, because 72440909 - 2⁸ = 72440653 is a prime.

It is a Chen prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (72440903) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 36220454 + 36220455.

It is an arithmetic number, because the mean of its divisors is an integer number (36220455).

Almost surely, 2^72440909 is an apocalyptic number.

It is an amenable number.

72440909 is a deficient number, since it is larger than the sum of its proper divisors (1).

72440909 is an equidigital number, since it uses as much as digits as its factorization.

72440909 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 18144, while the sum is 35.

The square root of 72440909 is about 8511.2225326330. Note that the first 3 decimals coincide. The cubic root of 72440909 is about 416.8642293685.

The spelling of 72440909 in words is "seventy-two million, four hundred forty thousand, nine hundred nine".