20661366065 has 8 divisors (see below), whose sum is σ = 24806611368. Its totient is φ = 16520444800.

The previous prime is 20661366031. The next prime is 20661366073. The reversal of 20661366065 is 56066316602.

It is a happy number.

It can be written as a sum of positive squares in 4 ways, for example, as 1881130384 + 18780235681 = 43372^2 + 137041^2 .

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

It is not a de Polignac number, because 20661366065 - 2³⁰ = 19587624241 is a prime.

It is a Duffinian number.

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 1070486 + ... + 1089615.

It is an arithmetic number, because the mean of its divisors is an integer number (3100826421).

Almost surely, 2^20661366065 is an apocalyptic number.

It is an amenable number.

20661366065 is a deficient number, since it is larger than the sum of its proper divisors (4145245303).

20661366065 is a wasteful number, since it uses less digits than its factorization.

20661366065 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2162019.

The product of its (nonzero) digits is 233280, while the sum is 41.

The spelling of 20661366065 in words is "twenty billion, six hundred sixty-one million, three hundred sixty-six thousand, sixty-five".