20785203857 has 16 divisors (see below), whose sum is σ = 23489616384. Its totient is φ = 18220944000.

The previous prime is 20785203823. The next prime is 20785203863. The reversal of 20785203857 is 75830258702.

It is a happy number.

It is a cyclic number.

It is not a de Polignac number, because 20785203857 - 2⁶ = 20785203793 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (20785203877) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 12638 + ... + 204279.

It is an arithmetic number, because the mean of its divisors is an integer number (1468101024).

Almost surely, 2^20785203857 is an apocalyptic number.

It is an amenable number.

20785203857 is a deficient number, since it is larger than the sum of its proper divisors (2704412527).

20785203857 is a wasteful number, since it uses less digits than its factorization.

20785203857 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 217240.

The product of its (nonzero) digits is 940800, while the sum is 47.

The spelling of 20785203857 in words is "twenty billion, seven hundred eighty-five million, two hundred three thousand, eight hundred fifty-seven".