12721780 has 72 divisors (see below), whose sum is σ = 29707776. Its totient is φ = 4569600.

The previous prime is 12721777. The next prime is 12721789. The reversal of 12721780 is 8712721.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (12721789) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 179145 + ... + 179215.

It is an arithmetic number, because the mean of its divisors is an integer number (412608).

Almost surely, 2^12721780 is an apocalyptic number.

12721780 is a gapful number since it is divisible by the number (10) 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 12721780, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (14853888).

12721780 is an abundant number, since it is smaller than the sum of its proper divisors (16985996).

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

12721780 is a wasteful number, since it uses less digits than its factorization.

12721780 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 145 (or 126 counting only the distinct ones).

The product of its (nonzero) digits is 1568, while the sum is 28.

The square root of 12721780 is about 3566.7604349045. The cubic root of 12721780 is about 233.4439520847.

The spelling of 12721780 in words is "twelve million, seven hundred twenty-one thousand, seven hundred eighty".