1287780 has 72 divisors (see below), whose sum is σ = 3935232. Its totient is φ = 314496.

The previous prime is 1287761. The next prime is 1287787. The reversal of 1287780 is 877821.

It is not an unprimeable number, because it can be changed into a prime (1287787) by changing a digit.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 10077 + ... + 10203.

It is an arithmetic number, because the mean of its divisors is an integer number (54656).

2^1287780 is an apocalyptic number.

1287780 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 1287780, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (1967616).

1287780 is an abundant number, since it is smaller than the sum of its proper divisors (2647452).

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

1287780 is a wasteful number, since it uses less digits than its factorization.

1287780 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 165 (or 150 counting only the distinct ones).

The product of its (nonzero) digits is 6272, while the sum is 33.

The square root of 1287780 is about 1134.8039478254. The cubic root of 1287780 is about 108.7962413999.

The spelling of 1287780 in words is "one million, two hundred eighty-seven thousand, seven hundred eighty".