21691961596369 has 7 divisors (see below), whose sum is σ = 21822636063817. Its totient is φ = 21562069610762.

The previous prime is 21691961596309. The next prime is 21691961596381. The reversal of 21691961596369 is 96369516919612.

The square root of 21691961596369 is 4657463.

The cubic root of 21691961596369 is 27889.

It is a perfect power (a square, a cube, a 6-th power), and thus also a powerful number.

It is not a de Polignac number, because 21691961596369 - 2⁷ = 21691961596241 is a prime.

It is a super-3 number, since 3×21691961596369³ (a number of 41 digits) contains 333 as substring. Note that it is a super-d number also for d = 2.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (21691961596309) by changing a digit.

It is a polite number, since it can be written in 6 ways as a sum of consecutive naturals, for example, 129891985524 + ... + 129891985690.

Almost surely, 2^{21691961596369} is an apocalyptic number.

21691961596369 is the 4657463-rd square number.

21691961596369 is the 2328732-nd centered octagonal number.

It is an amenable number.

21691961596369 is a deficient number, since it is larger than the sum of its proper divisors (130674467448).

21691961596369 is an frugal number, since it uses more digits than its factorization.

21691961596369 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1002 (or 167 counting only the distinct ones).

The product of its digits is 255091680, while the sum is 73.

The spelling of 21691961596369 in words is "twenty-one trillion, six hundred ninety-one billion, nine hundred sixty-one million, five hundred ninety-six thousand, three hundred sixty-nine".