801399509 has 2 divisors, whose sum is σ = 801399510. Its totient is φ = 801399508.

The previous prime is 801399479. The next prime is 801399551. The reversal of 801399509 is 905993108.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 768509284 + 32890225 = 27722^2 + 5735^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-801399509 is a prime.

It is a self number, because there is not a number n which added to its sum of digits gives 801399509.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (801399559) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 400699754 + 400699755.

It is an arithmetic number, because the mean of its divisors is an integer number (400699755).

Almost surely, 2^801399509 is an apocalyptic number.

It is an amenable number.

801399509 is a deficient number, since it is larger than the sum of its proper divisors (1).

801399509 is an equidigital number, since it uses as much as digits as its factorization.

801399509 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 87480, while the sum is 44.

The square root of 801399509 is about 28309.0004945424. Note that the first 3 decimals coincide. The cubic root of 801399509 is about 928.8587801435.

The spelling of 801399509 in words is "eight hundred one million, three hundred ninety-nine thousand, five hundred nine".