20709117245 has 18 divisors (see below), whose sum is σ = 25085190078. Its totient is φ = 16412579568.

The previous prime is 20709117229. The next prime is 20709117251. The reversal of 20709117245 is 54271190702.

It is a happy number.

It can be written as a sum of positive squares in only one way, i.e., 16567293796 + 4141823449 = 128714^2 + 64357^2 .

It is not a de Polignac number, because 20709117245 - 2⁴ = 20709117229 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 20709117199 and 20709117208.

It is a congruent number.

It is an unprimeable number.

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 17 ways as a sum of consecutive naturals, for example, 44727884 + ... + 44728346.

It is an arithmetic number, because the mean of its divisors is an integer number (1393621671).

Almost surely, 2^20709117245 is an apocalyptic number.

It is an amenable number.

20709117245 is a deficient number, since it is larger than the sum of its proper divisors (4376072833).

20709117245 is an frugal number, since it uses more digits than its factorization.

20709117245 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1209 (or 607 counting only the distinct ones).

The product of its (nonzero) digits is 35280, while the sum is 38.

Multiplying 20709117245 by its product of nonzero digits (35280), we get a square (730617656403600 = 27029940²).

The spelling of 20709117245 in words is "twenty billion, seven hundred nine million, one hundred seventeen thousand, two hundred forty-five".