8491780 has 60 divisors (see below), whose sum is σ = 20292300. Its totient is φ = 2981440.

The previous prime is 8491753. The next prime is 8491801. The reversal of 8491780 is 871948.

It can be written as a sum of positive squares in 2 ways, for example, as 3748096 + 4743684 = 1936^2 + 2178^2 .

It is a super-2 number, since 2×8491780² = 144220655136800, which contains 22 as substring.

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (7) of ones.

It is a polite number, since it can be written in 19 ways as a sum of consecutive naturals, for example, 292806 + ... + 292834.

It is an arithmetic number, because the mean of its divisors is an integer number (338205).

Almost surely, 2^8491780 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 8491780, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (10146150).

8491780 is an abundant number, since it is smaller than the sum of its proper divisors (11800520).

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

8491780 is a wasteful number, since it uses less digits than its factorization.

8491780 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 82 (or 47 counting only the distinct ones).

The product of its (nonzero) digits is 16128, while the sum is 37.

The square root of 8491780 is about 2914.0658880677. The cubic root of 8491780 is about 204.0169472016.

It can be divided in two parts, 8491 and 780, that multiplied together give a triangular number (6622980 = T₃₆₃₉).

The spelling of 8491780 in words is "eight million, four hundred ninety-one thousand, seven hundred eighty".