20217850897 has 4 divisors (see below), whose sum is σ = 20688033520. Its totient is φ = 19747668276.

The previous prime is 20217850889. The next prime is 20217850907. The reversal of 20217850897 is 79805871202.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is a cyclic number.

It is not a de Polignac number, because 20217850897 - 2³ = 20217850889 is a prime.

It is a super-2 number, since 2×20217850897² (a number of 21 digits) contains 22 as substring.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 20217850897.

It is not an unprimeable number, because it can be changed into a prime (20217850817) 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, 235091247 + ... + 235091332.

It is an arithmetic number, because the mean of its divisors is an integer number (5172008380).

Almost surely, 2^20217850897 is an apocalyptic number.

It is an amenable number.

20217850897 is a deficient number, since it is larger than the sum of its proper divisors (470182623).

20217850897 is an equidigital number, since it uses as much as digits as its factorization.

20217850897 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 470182622.

The product of its (nonzero) digits is 564480, while the sum is 49.

The spelling of 20217850897 in words is "twenty billion, two hundred seventeen million, eight hundred fifty thousand, eight hundred ninety-seven".