20066355561 has 16 divisors (see below), whose sum is σ = 30632217984. Its totient is φ = 11445896064.

The previous prime is 20066355479. The next prime is 20066355593. The reversal of 20066355561 is 16555366002.

It is not a de Polignac number, because 20066355561 - 2¹¹ = 20066353513 is a prime.

It is a Curzon number.

It is not an unprimeable number, because it can be changed into a prime (20066355061) 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, 846060 + ... + 869453.

It is an arithmetic number, because the mean of its divisors is an integer number (1914513624).

Almost surely, 2^20066355561 is an apocalyptic number.

20066355561 is a gapful number since it is divisible by the number (21) formed by its first and last digit.

It is an amenable number.

20066355561 is a deficient number, since it is larger than the sum of its proper divisors (10565862423).

20066355561 is a wasteful number, since it uses less digits than its factorization.

20066355561 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1716080.

The product of its (nonzero) digits is 162000, while the sum is 39.

The spelling of 20066355561 in words is "twenty billion, sixty-six million, three hundred fifty-five thousand, five hundred sixty-one".