20397581017 has 4 divisors (see below), whose sum is σ = 22251906576. Its totient is φ = 18543255460.

The previous prime is 20397580963. The next prime is 20397581047. The reversal of 20397581017 is 71018579302.

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 a de Polignac number, because none of the positive numbers 2^k-20397581017 is a prime.

It is a super-2 number, since 2×20397581017² (a number of 21 digits) contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (20397581047) 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, 927162763 + ... + 927162784.

It is an arithmetic number, because the mean of its divisors is an integer number (5562976644).

Almost surely, 2^20397581017 is an apocalyptic number.

It is an amenable number.

20397581017 is a deficient number, since it is larger than the sum of its proper divisors (1854325559).

20397581017 is a wasteful number, since it uses less digits than its factorization.

20397581017 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1854325558.

The product of its (nonzero) digits is 105840, while the sum is 43.

The spelling of 20397581017 in words is "twenty billion, three hundred ninety-seven million, five hundred eighty-one thousand, seventeen".