19617643969 has 81 divisors (see below), whose sum is σ = 26897380419. Its totient is φ = 14252810880.

The previous prime is 19617643967. The next prime is 19617643987. The reversal of 19617643969 is 96934671691.

The square root of 19617643969 is 140063.

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., 15273252225 + 4344391744 = 123585^2 + 65912^2 .

It is not a de Polignac number, because 19617643969 - 2¹ = 19617643967 is a prime.

It is a super-2 number, since 2×19617643969² (a number of 21 digits) contains 22 as substring.

It is not an unprimeable number, because it can be changed into a prime (19617643967) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 80 ways as a sum of consecutive naturals, for example, 183342414 + ... + 183342520.

Almost surely, 2^19617643969 is an apocalyptic number.

19617643969 is the 140063-rd square number.

19617643969 is the 70032-nd centered octagonal number.

It is an amenable number.

19617643969 is a deficient number, since it is larger than the sum of its proper divisors (7279736450).

19617643969 is a wasteful number, since it uses less digits than its factorization.

19617643969 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 284 (or 142 counting only the distinct ones).

The product of its digits is 13226976, while the sum is 61.

The spelling of 19617643969 in words is "nineteen billion, six hundred seventeen million, six hundred forty-three thousand, nine hundred sixty-nine".