817969409 has 2 divisors, whose sum is σ = 817969410. Its totient is φ = 817969408.

The previous prime is 817969403. The next prime is 817969417. The reversal of 817969409 is 904969718.

It is a happy number.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 817960000 + 9409 = 28600^2 + 97^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-817969409 is a prime.

It is a Chen prime.

It is not a weakly prime, because it can be changed into another prime (817969403) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 408984704 + 408984705.

It is an arithmetic number, because the mean of its divisors is an integer number (408984705).

Almost surely, 2^817969409 is an apocalyptic number.

It is an amenable number.

817969409 is a deficient number, since it is larger than the sum of its proper divisors (1).

817969409 is an equidigital number, since it uses as much as digits as its factorization.

817969409 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 979776, while the sum is 53.

The square root of 817969409 is about 28600.1644925340. The cubic root of 817969409 is about 935.2169167001.

It can be divided in two parts, 81796 and 9409, that multiplied together give a square (769618564 = 27742²).

The spelling of 817969409 in words is "eight hundred seventeen million, nine hundred sixty-nine thousand, four hundred nine".