20420633665 has 32 divisors (see below), whose sum is σ = 26421759360. Its totient is φ = 15094447104.

The previous prime is 20420633641. The next prime is 20420633669. The reversal of 20420633665 is 56633602402.

It is a cyclic number.

It is not a de Polignac number, because 20420633665 - 2²¹ = 20418536513 is a prime.

It is not an unprimeable number, because it can be changed into a prime (20420633669) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 4395834 + ... + 4400476.

It is an arithmetic number, because the mean of its divisors is an integer number (825679980).

Almost surely, 2^20420633665 is an apocalyptic number.

It is an amenable number.

20420633665 is a deficient number, since it is larger than the sum of its proper divisors (6001125695).

20420633665 is a wasteful number, since it uses less digits than its factorization.

20420633665 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 5601.

The product of its (nonzero) digits is 155520, while the sum is 37.

The spelling of 20420633665 in words is "twenty billion, four hundred twenty million, six hundred thirty-three thousand, six hundred sixty-five".