20720974617 has 36 divisors (see below), whose sum is σ = 35757900516. Its totient is φ = 11520532800.

The previous prime is 20720974601. The next prime is 20720974657. The reversal of 20720974617 is 71647902702.

20720974617 is a `hidden beast` number, since 2 + 0 + 7 + 20 + 9 + 7 + 4 + 617 = 666.

It can be written as a sum of positive squares in 2 ways, for example, as 19861546761 + 859427856 = 140931^2 + 29316^2 .

It is not a de Polignac number, because 20720974617 - 2⁴ = 20720974601 is a prime.

It is not an unprimeable number, because it can be changed into a prime (20720974657) 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 35 ways as a sum of consecutive naturals, for example, 618634 + ... + 651267.

Almost surely, 2^20720974617 is an apocalyptic number.

It is an amenable number.

20720974617 is a deficient number, since it is larger than the sum of its proper divisors (15036925899).

20720974617 is a wasteful number, since it uses less digits than its factorization.

20720974617 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1269958 (or 1269948 counting only the distinct ones).

The product of its (nonzero) digits is 296352, while the sum is 45.

The spelling of 20720974617 in words is "twenty billion, seven hundred twenty million, nine hundred seventy-four thousand, six hundred seventeen".