66789440 has 56 divisors (see below), whose sum is σ = 163369752. Its totient is φ = 25989120.

The previous prime is 66789439. The next prime is 66789461. The reversal of 66789440 is 4498766.

It can be written as a sum of positive squares in 4 ways, for example, as 40246336 + 26543104 = 6344^2 + 5152^2 .

It is a junction number, because it is equal to n+sod(n) for n = 66789391 and 66789400.

It is a congruent number.

It is an unprimeable number.

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 7 ways as a sum of consecutive naturals, for example, 9020 + ... + 14660.

It is an arithmetic number, because the mean of its divisors is an integer number (2917317).

Almost surely, 2^66789440 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 66789440, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (81684876).

66789440 is an abundant number, since it is smaller than the sum of its proper divisors (96580312).

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

66789440 is a wasteful number, since it uses less digits than its factorization.

66789440 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 5695 (or 5685 counting only the distinct ones).

The product of its (nonzero) digits is 290304, while the sum is 44.

The square root of 66789440 is about 8172.4806515525. The cubic root of 66789440 is about 405.7288911340.

The spelling of 66789440 in words is "sixty-six million, seven hundred eighty-nine thousand, four hundred forty".