20851091712 has 432 divisors, whose sum is σ = 68702437440. Its totient is φ = 6232596480.

The previous prime is 20851091711. The next prime is 20851091717. The reversal of 20851091712 is 21719015802.

It is a happy number.

It is a tau number, because it is divible by the number of its divisors (432).

It is a Harshad number since it is a multiple of its sum of digits (36).

It is not an unprimeable number, because it can be changed into a prime (20851091711) by changing a digit.

It is a polite number, since it can be written in 47 ways as a sum of consecutive naturals, for example, 89489548 + ... + 89489780.

It is an arithmetic number, because the mean of its divisors is an integer number (159033420).

Almost surely, 2^20851091712 is an apocalyptic number.

20851091712 is a gapful number since it is divisible by the number (22) formed by its first and last digit.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 20851091712, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (34351218720).

20851091712 is an abundant number, since it is smaller than the sum of its proper divisors (47851345728).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

20851091712 is a wasteful number, since it uses less digits than its factorization.

20851091712 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 387 (or 356 counting only the distinct ones).

The product of its (nonzero) digits is 10080, while the sum is 36.

The spelling of 20851091712 in words is "twenty billion, eight hundred fifty-one million, ninety-one thousand, seven hundred twelve".