20661379072 has 56 divisors (see below), whose sum is σ = 41430837636. Its totient is φ = 10303045632.

The previous prime is 20661379051. The next prime is 20661379091. The reversal of 20661379072 is 27097316602.

It can be written as a sum of positive squares in 2 ways, for example, as 20570443776 + 90935296 = 143424^2 + 9536^2 .

It is an unprimeable number.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 3249048 + ... + 3255400.

Almost surely, 2^20661379072 is an apocalyptic number.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 20661379072, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (20715418818).

20661379072 is an abundant number, since it is smaller than the sum of its proper divisors (20769458564).

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

20661379072 is an frugal number, since it uses more digits than its factorization.

20661379072 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 6776 (or 6752 counting only the distinct ones).

The product of its (nonzero) digits is 190512, while the sum is 43.

The spelling of 20661379072 in words is "twenty billion, six hundred sixty-one million, three hundred seventy-nine thousand, seventy-two".