72805409 has 2 divisors, whose sum is σ = 72805410. Its totient is φ = 72805408.

The previous prime is 72805367. The next prime is 72805451. The reversal of 72805409 is 90450827.

It is a happy number.

It is a balanced prime because it is at equal distance from previous prime (72805367) and next prime (72805451).

It can be written as a sum of positive squares in only one way, i.e., 71656225 + 1149184 = 8465^2 + 1072^2 .

It is a cyclic number.

It is not a de Polignac number, because 72805409 - 2²⁰ = 71756833 is a prime.

It is not a weakly prime, because it can be changed into another prime (72805489) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 36402704 + 36402705.

It is an arithmetic number, because the mean of its divisors is an integer number (36402705).

Almost surely, 2^72805409 is an apocalyptic number.

It is an amenable number.

72805409 is a deficient number, since it is larger than the sum of its proper divisors (1).

72805409 is an equidigital number, since it uses as much as digits as its factorization.

72805409 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 20160, while the sum is 35.

The square root of 72805409 is about 8532.6085694821. The cubic root of 72805409 is about 417.5622367687.

The spelling of 72805409 in words is "seventy-two million, eight hundred five thousand, four hundred nine".