6665780 has 48 divisors (see below), whose sum is σ = 15664320. Its totient is φ = 2361600.

The previous prime is 6665777. The next prime is 6665797. The reversal of 6665780 is 875666.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 8651 + ... + 9389.

It is an arithmetic number, because the mean of its divisors is an integer number (326340).

Almost surely, 2^6665780 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 6665780, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (7832160).

6665780 is an abundant number, since it is smaller than the sum of its proper divisors (8998540).

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

6665780 is a wasteful number, since it uses less digits than its factorization.

6665780 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 800 (or 798 counting only the distinct ones).

The product of its (nonzero) digits is 60480, while the sum is 38.

The square root of 6665780 is about 2581.8171895004. The cubic root of 6665780 is about 188.1988615535.

It can be divided in two parts, 6665 and 780, that multiplied together give a triangular number (5198700 = T₃₂₂₄).

The spelling of 6665780 in words is "six million, six hundred sixty-five thousand, seven hundred eighty".