669778560 has 432 divisors, whose sum is σ = 2626852410. Its totient is φ = 157132800.

The previous prime is 669778553. The next prime is 669778567. The reversal of 669778560 is 65877966.

It is a happy number.

669778560 is a `hidden beast` number, since 6 + 6 + 9 + 7 + 78 + 560 = 666.

It is an interprime number because it is at equal distance from previous prime (669778553) and next prime (669778567).

It can be written as a sum of positive squares in only one way, i.e., 602800704 + 66977856 = 24552^2 + 8184^2 .

It is a junction number, because it is equal to n+sod(n) for n = 669778497 and 669778506.

It is not an unprimeable number, because it can be changed into a prime (669778567) by changing a digit.

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 53 ways as a sum of consecutive naturals, for example, 21605745 + ... + 21605775.

Almost surely, 2^669778560 is an apocalyptic number.

669778560 is a gapful number since it is divisible by the number (60) 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 669778560, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (1313426205).

669778560 is an abundant number, since it is smaller than the sum of its proper divisors (1957073850).

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

669778560 is a wasteful number, since it uses less digits than its factorization.

669778560 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 109 (or 52 counting only the distinct ones).

The product of its (nonzero) digits is 3810240, while the sum is 54.

The square root of 669778560 is about 25880.0803708180. The cubic root of 669778560 is about 874.9375999038.

The spelling of 669778560 in words is "six hundred sixty-nine million, seven hundred seventy-eight thousand, five hundred sixty".