1268387640 has 256 divisors, whose sum is σ = 4630953600. Its totient is φ = 306892800.

The previous prime is 1268387633. The next prime is 1268387669. The reversal of 1268387640 is 467838621.

1268387640 is a `hidden beast` number, since 1 + 268 + 387 + 6 + 4 + 0 = 666.

It is a Smith number, since the sum of its digits (45) coincides with the sum of the digits of its prime factors.

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

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 63 ways as a sum of consecutive naturals, for example, 855700 + ... + 857180.

Almost surely, 2^1268387640 is an apocalyptic number.

1268387640 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 1268387640, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (2315476800).

1268387640 is an abundant number, since it is smaller than the sum of its proper divisors (3362565960).

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

1268387640 is a wasteful number, since it uses less digits than its factorization.

1268387640 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1575 (or 1565 counting only the distinct ones).

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

The square root of 1268387640 is about 35614.4302214706. The cubic root of 1268387640 is about 1082.4736509684.

The spelling of 1268387640 in words is "one billion, two hundred sixty-eight million, three hundred eighty-seven thousand, six hundred forty".