20005781885 has 8 divisors (see below), whose sum is σ = 24182172216. Its totient is φ = 15887802880.

The previous prime is 20005781837. The next prime is 20005781923. The reversal of 20005781885 is 58818750002.

It can be written as a sum of positive squares in 4 ways, for example, as 7591811161 + 12413970724 = 87131^2 + 111418^2 .

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

It is not a de Polignac number, because 20005781885 - 2²⁴ = 19989004669 is a prime.

It is a Duffinian number.

It is a Curzon number.

It is a congruent 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, 14602076 + ... + 14603445.

It is an arithmetic number, because the mean of its divisors is an integer number (3022771527).

Almost surely, 2^20005781885 is an apocalyptic number.

It is an amenable number.

20005781885 is a deficient number, since it is larger than the sum of its proper divisors (4176390331).

20005781885 is a wasteful number, since it uses less digits than its factorization.

20005781885 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 29205663.

The product of its (nonzero) digits is 179200, while the sum is 44.

The spelling of 20005781885 in words is "twenty billion, five million, seven hundred eighty-one thousand, eight hundred eighty-five".