20717175551 has 4 divisors (see below), whose sum is σ = 20732883600. Its totient is φ = 20701467504.

The previous prime is 20717175539. The next prime is 20717175593. The reversal of 20717175551 is 15557171702.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 15557171702 = 2 ⋅7778585851.

It is a cyclic number.

It is not a de Polignac number, because 20717175551 - 2⁶ = 20717175487 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 20717175499 and 20717175508.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (20717172551) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 7852046 + ... + 7854683.

It is an arithmetic number, because the mean of its divisors is an integer number (5183220900).

Almost surely, 2^20717175551 is an apocalyptic number.

20717175551 is a deficient number, since it is larger than the sum of its proper divisors (15708049).

20717175551 is a wasteful number, since it uses less digits than its factorization.

20717175551 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 15708048.

The product of its (nonzero) digits is 85750, while the sum is 41.

The spelling of 20717175551 in words is "twenty billion, seven hundred seventeen million, one hundred seventy-five thousand, five hundred fifty-one".