20661655666157 has 8 divisors (see below), whose sum is σ = 22571337087360. Its totient is φ = 18757199092960.

The previous prime is 20661655666133. The next prime is 20661655666177. The reversal of 20661655666157 is 75166655616602.

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

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-20661655666157 is a prime.

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 20661655666157.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (20661655666177) 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, 1306203728 + ... + 1306219545.

It is an arithmetic number, because the mean of its divisors is an integer number (2821417135920).

Almost surely, 2^{20661655666157} is an apocalyptic number.

It is an amenable number.

20661655666157 is a deficient number, since it is larger than the sum of its proper divisors (1909681421203).

20661655666157 is a wasteful number, since it uses less digits than its factorization.

20661655666157 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2612424003.

The product of its (nonzero) digits is 81648000, while the sum is 62.

The spelling of 20661655666157 in words is "twenty trillion, six hundred sixty-one billion, six hundred fifty-five million, six hundred sixty-six thousand, one hundred fifty-seven".