20217571557 has 8 divisors (see below), whose sum is σ = 26959790976. Its totient is φ = 13476866592.

The previous prime is 20217571553. The next prime is 20217571597. The reversal of 20217571557 is 75517571202.

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

It is not a de Polignac number, because 20217571557 - 2² = 20217571553 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (20217571553) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 347088 + ... + 401129.

It is an arithmetic number, because the mean of its divisors is an integer number (3369973872).

Almost surely, 2^20217571557 is an apocalyptic number.

It is an amenable number.

20217571557 is a deficient number, since it is larger than the sum of its proper divisors (6742219419).

20217571557 is an equidigital number, since it uses as much as digits as its factorization.

20217571557 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 757227.

The product of its (nonzero) digits is 171500, while the sum is 42.

The spelling of 20217571557 in words is "twenty billion, two hundred seventeen million, five hundred seventy-one thousand, five hundred fifty-seven".