20405685085 has 8 divisors (see below), whose sum is σ = 24487706880. Its totient is φ = 16323958224.

The previous prime is 20405684983. The next prime is 20405685103. The reversal of 20405685085 is 58058650402.

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

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-20405685085 is a prime.

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, 129324 + ... + 239866.

It is an arithmetic number, because the mean of its divisors is an integer number (3060963360).

Almost surely, 2^20405685085 is an apocalyptic number.

It is an amenable number.

20405685085 is a deficient number, since it is larger than the sum of its proper divisors (4082021795).

20405685085 is a wasteful number, since it uses less digits than its factorization.

20405685085 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 147467.

The product of its (nonzero) digits is 384000, while the sum is 43.

The spelling of 20405685085 in words is "twenty billion, four hundred five million, six hundred eighty-five thousand, eighty-five".