20720666065 has 32 divisors (see below), whose sum is σ = 27782092800. Its totient is φ = 14705315520.

The previous prime is 20720666027. The next prime is 20720666123. The reversal of 20720666065 is 56066602702.

It is a happy number.

It is not a de Polignac number, because 20720666065 - 2¹⁷ = 20720534993 is a prime.

It is an unprimeable number.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 2974056 + ... + 2981014.

It is an arithmetic number, because the mean of its divisors is an integer number (868190400).

Almost surely, 2^20720666065 is an apocalyptic number.

It is an amenable number.

20720666065 is a deficient number, since it is larger than the sum of its proper divisors (7061426735).

20720666065 is a wasteful number, since it uses less digits than its factorization.

20720666065 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 8277.

The product of its (nonzero) digits is 181440, while the sum is 40.

The spelling of 20720666065 in words is "twenty billion, seven hundred twenty million, six hundred sixty-six thousand, sixty-five".