98405807809 has 15 divisors (see below), whose sum is σ = 103052564323. Its totient is φ = 93968563744.

The previous prime is 98405807789. The next prime is 98405807821. The reversal of 98405807809 is 90870850489.

The square root of 98405807809 is 313697.

It is a perfect power (a square), and thus also a powerful number.

It can be written as a sum of positive squares in only one way, i.e., 60508620225 + 37897187584 = 245985^2 + 194672^2 .

It is not a de Polignac number, because 98405807809 - 2⁷ = 98405807681 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (98405807839) by changing a digit.

It is a polite number, since it can be written in 14 ways as a sum of consecutive naturals, for example, 165945417 + ... + 165946009.

Almost surely, 2^98405807809 is an apocalyptic number.

98405807809 is the 313697-th square number.

98405807809 is the 156849-th centered octagonal number.

It is an amenable number.

98405807809 is a deficient number, since it is larger than the sum of its proper divisors (4646756514).

98405807809 is an frugal number, since it uses more digits than its factorization.

98405807809 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1278 (or 616 counting only the distinct ones).

The product of its (nonzero) digits is 5806080, while the sum is 58.

The spelling of 98405807809 in words is "ninety-eight billion, four hundred five million, eight hundred seven thousand, eight hundred nine".