7781286240 has 864 divisors, whose sum is σ = 35292348000. Its totient is φ = 1542094848.

The previous prime is 7781286217. The next prime is 7781286241. The reversal of 7781286240 is 426821877.

7781286240 is a `hidden beast` number, since 7 + 7 + 8 + 12 + 8 + 624 + 0 = 666.

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 (7781286241) by changing a digit.

It is a polite number, since it can be written in 143 ways as a sum of consecutive naturals, for example, 15593511 + ... + 15594009.

It is an arithmetic number, because the mean of its divisors is an integer number (40847625).

Almost surely, 2^7781286240 is an apocalyptic number.

7781286240 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 7781286240, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (17646174000).

7781286240 is an abundant number, since it is smaller than the sum of its proper divisors (27511061760).

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

7781286240 is a wasteful number, since it uses less digits than its factorization.

7781286240 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 564 (or 546 counting only the distinct ones).

The product of its (nonzero) digits is 301056, while the sum is 45.

The square root of 7781286240 is about 88211.5992372885. The cubic root of 7781286240 is about 1981.6051874554.

The spelling of 7781286240 in words is "seven billion, seven hundred eighty-one million, two hundred eighty-six thousand, two hundred forty".