7281368640 has 980 divisors, whose sum is σ = 32660007324. Its totient is φ = 1536288768.

The previous prime is 7281368603. The next prime is 7281368641. The reversal of 7281368640 is 468631827.

7281368640 is a `hidden beast` number, since 7 + 281 + 368 + 6 + 4 + 0 = 666.

It can be written as a sum of positive squares in 2 ways, for example, as 1792336896 + 5489031744 = 42336^2 + 74088^2 .

It is a tau number, because it is divible by the number of its divisors (980).

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

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (7281368641) by changing a digit.

It is a polite number, since it can be written in 139 ways as a sum of consecutive naturals, for example, 560105274 + ... + 560105286.

Almost surely, 2^7281368640 is an apocalyptic number.

7281368640 is a gapful number since it is divisible by the number (70) 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 7281368640, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (16330003662).

7281368640 is an abundant number, since it is smaller than the sum of its proper divisors (25378638684).

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

7281368640 is an frugal number, since it uses more digits than its factorization.

7281368640 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 76 (or 30 counting only the distinct ones).

The product of its (nonzero) digits is 387072, while the sum is 45.

The square root of 7281368640 is about 85330.9360079918. The cubic root of 7281368640 is about 1938.2256636073.

The spelling of 7281368640 in words is "seven billion, two hundred eighty-one million, three hundred sixty-eight thousand, six hundred forty".