20111171657 has 8 divisors (see below), whose sum is σ = 20494139400. Its totient is φ = 19728334080.

The previous prime is 20111171629. The next prime is 20111171671. The reversal of 20111171657 is 75617111102.

It can be written as a sum of positive squares in 4 ways, for example, as 8975857081 + 11135314576 = 94741^2 + 105524^2 .

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

It is a cyclic number.

It is not a de Polignac number, because 20111171657 - 2⁶ = 20111171593 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (20111171057) 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, 314219 + ... + 372767.

It is an arithmetic number, because the mean of its divisors is an integer number (2561767425).

Almost surely, 2^20111171657 is an apocalyptic number.

It is an amenable number.

20111171657 is a deficient number, since it is larger than the sum of its proper divisors (382967743).

20111171657 is an equidigital number, since it uses as much as digits as its factorization.

20111171657 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 65083.

The product of its (nonzero) digits is 2940, while the sum is 32.

Adding to 20111171657 its reverse (75617111102), we get a palindrome (95728282759).

The spelling of 20111171657 in words is "twenty billion, one hundred eleven million, one hundred seventy-one thousand, six hundred fifty-seven".