1691698226409 has 45 divisors (see below), whose sum is σ = 2684818109941. Its totient is φ = 1061332848000.

The previous prime is 1691698226359. The next prime is 1691698226431. The reversal of 1691698226409 is 9046228961961.

The square root of 1691698226409 is 1300653.

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

1691698226409 is a `hidden beast` number, since 1 + 6 + 91 + 69 + 82 + 2 + 6 + 409 = 666.

It can be written as a sum of positive squares in 4 ways, for example, as 65124488025 + 1626573738384 = 255195^2 + 1275372^2 .

It is not a de Polignac number, because 1691698226409 - 2¹¹ = 1691698224361 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (1691698226809) by changing a digit.

It is a polite number, since it can be written in 44 ways as a sum of consecutive naturals, for example, 198995659 + ... + 199004159.

Almost surely, 2^{1691698226409} is an apocalyptic number.

1691698226409 is the 1300653-rd square number.

1691698226409 is the 650327-th centered octagonal number.

It is an amenable number.

1691698226409 is a deficient number, since it is larger than the sum of its proper divisors (993119883532).

1691698226409 is an frugal number, since it uses more digits than its factorization.

1691698226409 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 17048 (or 8521 counting only the distinct ones).

The product of its (nonzero) digits is 20155392, while the sum is 63.

The spelling of 1691698226409 in words is "one trillion, six hundred ninety-one billion, six hundred ninety-eight million, two hundred twenty-six thousand, four hundred nine".