20051890866 has 96 divisors (see below), whose sum is σ = 51931376640. Its totient is φ = 5467299552.

The previous prime is 20051890861. The next prime is 20051890891. The reversal of 20051890866 is 66809815002.

It is not an unprimeable number, because it can be changed into a prime (20051890861) 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, 1276005 + ... + 1291623.

It is an arithmetic number, because the mean of its divisors is an integer number (540951840).

Almost surely, 2^20051890866 is an apocalyptic number.

It is a practical number, because each smaller number is the sum of distinct divisors of 20051890866, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (25965688320).

20051890866 is an abundant number, since it is smaller than the sum of its proper divisors (31879485774).

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

20051890866 is a wasteful number, since it uses less digits than its factorization.

20051890866 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 16100 (or 16097 counting only the distinct ones).

The product of its (nonzero) digits is 207360, while the sum is 45.

The spelling of 20051890866 in words is "twenty billion, fifty-one million, eight hundred ninety thousand, eight hundred sixty-six".