1247840640 has 160 divisors (see below), whose sum is σ = 4456449360. Its totient is φ = 332743680.

The previous prime is 1247840603. The next prime is 1247840641. The reversal of 1247840640 is 460487421.

1247840640 is a `hidden beast` number, since 1 + 2 + 4 + 7 + 8 + 4 + 0 + 640 = 666.

It is a tau number, because it is divible by the number of its divisors (160).

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 = 1247840595 and 1247840604.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1247840641) by changing a digit.

It is a polite number, since it can be written in 19 ways as a sum of consecutive naturals, for example, 39805 + ... + 63875.

Almost surely, 2^1247840640 is an apocalyptic number.

1247840640 is a gapful number since it is divisible by the number (10) 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 1247840640, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (2228224680).

1247840640 is an abundant number, since it is smaller than the sum of its proper divisors (3208608720).

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

1247840640 is an equidigital number, since it uses as much as digits as its factorization.

1247840640 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 24102 (or 24081 counting only the distinct ones).

The product of its (nonzero) digits is 43008, while the sum is 36.

The square root of 1247840640 is about 35324.7878974524. The cubic root of 1247840640 is about 1076.5966941440.

The spelling of 1247840640 in words is "one billion, two hundred forty-seven million, eight hundred forty thousand, six hundred forty".