20178396409369 has 27 divisors (see below), whose sum is σ = 23409433325439. Its totient is φ = 17377714656720.

The previous prime is 20178396409321. The next prime is 20178396409393. The reversal of 20178396409369 is 96390469387102.

The square root of 20178396409369 is 4492037.

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., 1764101958025 + 18414294451344 = 1328195^2 + 4291188^2 .

It is not a de Polignac number, because 20178396409369 - 2²¹ = 20178394312217 is a prime.

It is a super-2 number, since 2×20178396409369² (a number of 27 digits) contains 22 as substring.

It is not an unprimeable number, because it can be changed into a prime (20178396403369) by changing a digit.

It is a polite number, since it can be written in 26 ways as a sum of consecutive naturals, for example, 938824987 + ... + 938846479.

Almost surely, 2^{20178396409369} is an apocalyptic number.

20178396409369 is the 4492037-th square number.

20178396409369 is the 2246019-th centered octagonal number.

It is an amenable number.

20178396409369 is a deficient number, since it is larger than the sum of its proper divisors (3231036916070).

20178396409369 is an frugal number, since it uses more digits than its factorization.

20178396409369 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 43046 (or 21523 counting only the distinct ones).

The product of its (nonzero) digits is 105815808, while the sum is 67.

The spelling of 20178396409369 in words is "twenty trillion, one hundred seventy-eight billion, three hundred ninety-six million, four hundred nine thousand, three hundred sixty-nine".