666782550 has 192 divisors, whose sum is σ = 2157719040. Its totient is φ = 148210560.

The previous prime is 666782531. The next prime is 666782609. The reversal of 666782550 is 55287666.

It is a Harshad number since it is a multiple of its sum of digits (45).

It is a junction number, because it is equal to n+sod(n) for n = 666782496 and 666782505.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 95 ways as a sum of consecutive naturals, for example, 348697 + ... + 350603.

It is an arithmetic number, because the mean of its divisors is an integer number (11238120).

Almost surely, 2^666782550 is an apocalyptic number.

It is a practical number, because each smaller number is the sum of distinct divisors of 666782550, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (1078859520).

666782550 is an abundant number, since it is smaller than the sum of its proper divisors (1490936490).

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

666782550 is a wasteful number, since it uses less digits than its factorization.

666782550 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1972 (or 1961 counting only the distinct ones).

The product of its (nonzero) digits is 604800, while the sum is 45.

The square root of 666782550 is about 25822.1329483062. The cubic root of 666782550 is about 873.6310785119.

The spelling of 666782550 in words is "six hundred sixty-six million, seven hundred eighty-two thousand, five hundred fifty".