667520640 has 288 divisors, whose sum is σ = 2454704460. Its totient is φ = 167116800.

The previous prime is 667520617. The next prime is 667520641. The reversal of 667520640 is 46025766.

667520640 is a `hidden beast` number, since 6 + 6 + 7 + 5 + 2 + 0 + 640 = 666.

It can be written as a sum of positive squares in 6 ways, for example, as 636250176 + 31270464 = 25224^2 + 5592^2 .

It is a tau number, because it is divible by the number of its divisors (288).

It is a Harshad number since it is a multiple of its sum of digits (36).

It is a junction number, because it is equal to n+sod(n) for n = 667520595 and 667520604.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (667520641) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 35 ways as a sum of consecutive naturals, for example, 1664440 + ... + 1664840.

Almost surely, 2^667520640 is an apocalyptic number.

667520640 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 667520640, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (1227352230).

667520640 is an abundant number, since it is smaller than the sum of its proper divisors (1787183820).

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

667520640 is a wasteful number, since it uses less digits than its factorization.

667520640 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 460 (or 428 counting only the distinct ones).

The product of its (nonzero) digits is 60480, while the sum is 36.

The square root of 667520640 is about 25836.4208047477. The cubic root of 667520640 is about 873.9533127911.

The spelling of 667520640 in words is "six hundred sixty-seven million, five hundred twenty thousand, six hundred forty".