20985861900 has 144 divisors (see below), whose sum is σ = 63454938624. Its totient is φ = 5349630720.

The previous prime is 20985861899. The next prime is 20985861929. The reversal of 20985861900 is 916858902.

It is a happy number.

It is a super-2 number, since 2×20985861900² (a number of 21 digits) contains 22 as substring.

It is a self number, because there is not a number n which added to its sum of digits gives 20985861900.

It is an unprimeable number.

It is a polite number, since it can be written in 47 ways as a sum of consecutive naturals, for example, 588994 + ... + 623606.

It is an arithmetic number, because the mean of its divisors is an integer number (440659296).

Almost surely, 2^20985861900 is an apocalyptic number.

20985861900 is a gapful number since it is divisible by the number (20) 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 20985861900, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (31727469312).

20985861900 is an abundant number, since it is smaller than the sum of its proper divisors (42469076724).

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

20985861900 is a wasteful number, since it uses less digits than its factorization.

20985861900 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 34720 (or 34713 counting only the distinct ones).

The product of its (nonzero) digits is 311040, while the sum is 48.

The spelling of 20985861900 in words is "twenty billion, nine hundred eighty-five million, eight hundred sixty-one thousand, nine hundred".