998806356409 has 9 divisors (see below), whose sum is σ = 1011069122479. Its totient is φ = 986690593840.

The previous prime is 998806356407. The next prime is 998806356437. The reversal of 998806356409 is 904653608899.

The square root of 998806356409 is 999403.

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., 633700378809 + 365105977600 = 796053^2 + 604240^2 .

It is not a de Polignac number, because 998806356409 - 2¹ = 998806356407 is a prime.

It is a super-2 number, since 2×998806356409² (a number of 25 digits) contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (998806356407) by changing a digit.

It is a polite number, since it can be written in 8 ways as a sum of consecutive naturals, for example, 82944429 + ... + 82956469.

Almost surely, 2^998806356409 is an apocalyptic number.

998806356409 is the 999403-rd square number.

998806356409 is the 499702-nd centered octagonal number.

It is an amenable number.

998806356409 is a deficient number, since it is larger than the sum of its proper divisors (12262766070).

998806356409 is an frugal number, since it uses more digits than its factorization.

998806356409 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 24248 (or 12124 counting only the distinct ones).

The product of its (nonzero) digits is 100776960, while the sum is 67.

The spelling of 998806356409 in words is "nine hundred ninety-eight billion, eight hundred six million, three hundred fifty-six thousand, four hundred nine".