20611981824 has 160 divisors (see below), whose sum is σ = 64288135296. Its totient is φ = 5745377280.

The previous prime is 20611981807. The next prime is 20611981843. The reversal of 20611981824 is 42818911602.

It is a Harshad number since it is a multiple of its sum of digits (42).

It is an unprimeable number.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 417454 + ... + 464210.

Almost surely, 2^20611981824 is an apocalyptic number.

20611981824 is a gapful number since it is divisible by the number (24) 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 20611981824, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (32144067648).

20611981824 is an abundant number, since it is smaller than the sum of its proper divisors (43676153472).

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

20611981824 is an equidigital number, since it uses as much as digits as its factorization.

20611981824 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 46826 (or 46810 counting only the distinct ones).

The product of its (nonzero) digits is 55296, while the sum is 42.

The spelling of 20611981824 in words is "twenty billion, six hundred eleven million, nine hundred eighty-one thousand, eight hundred twenty-four".