20665011001657 has 16 divisors (see below), whose sum is σ = 23093750332800. Its totient is φ = 18327965526400.

The previous prime is 20665011001603. The next prime is 20665011001703. The reversal of 20665011001657 is 75610011056602.

It is a cyclic number.

It is not a de Polignac number, because 20665011001657 - 2³⁵ = 20630651263289 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (20665011041657) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 52367028 + ... + 52760170.

It is an arithmetic number, because the mean of its divisors is an integer number (1443359395800).

Almost surely, 2^{20665011001657} is an apocalyptic number.

It is an amenable number.

20665011001657 is a deficient number, since it is larger than the sum of its proper divisors (2428739331143).

20665011001657 is a wasteful number, since it uses less digits than its factorization.

20665011001657 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 509744.

The product of its (nonzero) digits is 75600, while the sum is 40.

Subtracting 20665011001657 from its reverse (75610011056602), we obtain a palindrome (54945000054945).

The spelling of 20665011001657 in words is "twenty trillion, six hundred sixty-five billion, eleven million, one thousand, six hundred fifty-seven".