2661643213220 has 48 divisors (see below), whose sum is σ = 5744155045440. Its totient is φ = 1035226272384.

The previous prime is 2661643213217. The next prime is 2661643213223. The reversal of 2661643213220 is 223123461662.

2661643213220 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is an interprime number because it is at equal distance from previous prime (2661643213217) and next prime (2661643213223).

It is not an unprimeable number, because it can be changed into a prime (2661643213223) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 29507 + ... + 2307413.

It is an arithmetic number, because the mean of its divisors is an integer number (119669896780).

Almost surely, 2^{2661643213220} is an apocalyptic number.

2661643213220 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 2661643213220, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (2872077522720).

2661643213220 is an abundant number, since it is smaller than the sum of its proper divisors (3082511832220).

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

2661643213220 is a wasteful number, since it uses less digits than its factorization.

2661643213220 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2279532 (or 2279530 counting only the distinct ones).

The product of its (nonzero) digits is 124416, while the sum is 38.

Adding to 2661643213220 its reverse (223123461662), we get a palindrome (2884766674882).

The spelling of 2661643213220 in words is "two trillion, six hundred sixty-one billion, six hundred forty-three million, two hundred thirteen thousand, two hundred twenty".