20517812553 has 8 divisors (see below), whose sum is σ = 31265238208. Its totient is φ = 11724464304.

The previous prime is 20517812543. The next prime is 20517812569. The reversal of 20517812553 is 35521871502.

It is a sphenic number, since it is the product of 3 distinct primes.

It is not a de Polignac number, because 20517812553 - 2⁵ = 20517812521 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (20517812543) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 488519326 + ... + 488519367.

It is an arithmetic number, because the mean of its divisors is an integer number (3908154776).

Almost surely, 2^20517812553 is an apocalyptic number.

It is an amenable number.

20517812553 is a deficient number, since it is larger than the sum of its proper divisors (10747425655).

20517812553 is an equidigital number, since it uses as much as digits as its factorization.

20517812553 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 977038703.

The product of its (nonzero) digits is 84000, while the sum is 39.

The spelling of 20517812553 in words is "twenty billion, five hundred seventeen million, eight hundred twelve thousand, five hundred fifty-three".