1281720 has 64 divisors (see below), whose sum is σ = 4199040. Its totient is φ = 310400.

The previous prime is 1281703. The next prime is 1281727. The reversal of 1281720 is 271821.

It is a super-3 number, since 3×1281720³ = 6316852528033344000, which contains 333 as substring.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1281727) 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 15 ways as a sum of consecutive naturals, for example, 835 + ... + 1805.

It is an arithmetic number, because the mean of its divisors is an integer number (65610).

2^1281720 is an apocalyptic number.

1281720 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 1281720, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (2099520).

1281720 is an abundant number, since it is smaller than the sum of its proper divisors (2917320).

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

1281720 is a wasteful number, since it uses less digits than its factorization.

1281720 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 996 (or 992 counting only the distinct ones).

The product of its (nonzero) digits is 224, while the sum is 21.

The square root of 1281720 is about 1132.1307345002. The cubic root of 1281720 is about 108.6253162120.

The spelling of 1281720 in words is "one million, two hundred eighty-one thousand, seven hundred twenty".