20851359999 has 32 divisors (see below), whose sum is σ = 28275793920. Its totient is φ = 13666568832.

The previous prime is 20851359983. The next prime is 20851360021. The reversal of 20851359999 is 99995315802.

It is a Cunningham number, because it is equal to 380⁴-1.

It is not a de Polignac number, because 20851359999 - 2⁴ = 20851359983 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (20851359929) by changing a digit.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 28446237 + ... + 28446969.

It is an arithmetic number, because the mean of its divisors is an integer number (883618560).

Almost surely, 2^20851359999 is an apocalyptic number.

20851359999 is a deficient number, since it is larger than the sum of its proper divisors (7424433921).

20851359999 is a wasteful number, since it uses less digits than its factorization.

20851359999 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1439.

The product of its (nonzero) digits is 7873200, while the sum is 60.

The spelling of 20851359999 in words is "twenty billion, eight hundred fifty-one million, three hundred fifty-nine thousand, nine hundred ninety-nine".