20401009985 has 4 divisors (see below), whose sum is σ = 24481211988. Its totient is φ = 16320807984.

The previous prime is 20401009931. The next prime is 20401009991. The reversal of 20401009985 is 58990010402.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 9872608321 + 10528401664 = 99361^2 + 102608^2 .

It is a cyclic number.

It is not a de Polignac number, because 20401009985 - 2¹⁰ = 20401008961 is a prime.

It is a Duffinian number.

It is an unprimeable number.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 2040100994 + ... + 2040101003.

It is an arithmetic number, because the mean of its divisors is an integer number (6120302997).

Almost surely, 2^20401009985 is an apocalyptic number.

It is an amenable number.

20401009985 is a deficient number, since it is larger than the sum of its proper divisors (4080202003).

20401009985 is an equidigital number, since it uses as much as digits as its factorization.

20401009985 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 4080202002.

The product of its (nonzero) digits is 25920, while the sum is 38.

The spelling of 20401009985 in words is "twenty billion, four hundred one million, nine thousand, nine hundred eighty-five".