20661661555061 has 8 divisors (see below), whose sum is σ = 21882547597920. Its totient is φ = 19454118529392.

The previous prime is 20661661555057. The next prime is 20661661555069. The reversal of 20661661555061 is 16055516616602.

It is a happy number.

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 20661661555061 - 2² = 20661661555057 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (20661661555069) 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, 3335751110 + ... + 3335757303.

It is an arithmetic number, because the mean of its divisors is an integer number (2735318449740).

Almost surely, 2^{20661661555061} is an apocalyptic number.

It is an amenable number.

20661661555061 is a deficient number, since it is larger than the sum of its proper divisors (1220886042859).

20661661555061 is a wasteful number, since it uses less digits than its factorization.

20661661555061 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 6671508595.

The product of its (nonzero) digits is 1944000, while the sum is 50.

The spelling of 20661661555061 in words is "twenty trillion, six hundred sixty-one billion, six hundred sixty-one million, five hundred fifty-five thousand, sixty-one".