19540405369 has 3 divisors (see below), whose sum is σ = 19540545157. Its totient is φ = 19540265582.

The previous prime is 19540405309. The next prime is 19540405399. The reversal of 19540405369 is 96350404591.

The square root of 19540405369 is 139787.

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

It is a semiprime because it is the product of two primes, and also a brilliant number, because the two primes have the same length, and also an emirpimes, since its reverse is a distinct semiprime: 96350404591 = 7 ⋅13764343513.

It is not a de Polignac number, because 19540405369 - 2⁹ = 19540404857 is a prime.

It is a super-2 number, since 2×19540405369² (a number of 21 digits) contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (19540405309) by changing a digit.

It is a polite number, since it can be written in 2 ways as a sum of consecutive naturals, for example, 69894 + ... + 209680.

Almost surely, 2^19540405369 is an apocalyptic number.

19540405369 is the 139787-th square number.

19540405369 is the 69894-th centered octagonal number.

It is an amenable number.

19540405369 is a deficient number, since it is larger than the sum of its proper divisors (139788).

19540405369 is an frugal number, since it uses more digits than its factorization.

19540405369 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 279574 (or 139787 counting only the distinct ones).

The product of its (nonzero) digits is 583200, while the sum is 46.

The spelling of 19540405369 in words is "nineteen billion, five hundred forty million, four hundred five thousand, three hundred sixty-nine".