1287640395 has 80 divisors (see below), whose sum is σ = 2428557120. Its totient is φ = 651442176.

The previous prime is 1287640391. The next prime is 1287640429. The reversal of 1287640395 is 5930467821.

1287640395 is digitally balanced in base 10, because in such base it contains all the possibile digits an equal number of times.

It is not a de Polignac number, because 1287640395 - 2² = 1287640391 is a prime.

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

1287640395 is strictly pandigital in base 10.

It is a self number, because there is not a number n which added to its sum of digits gives 1287640395.

It is not an unprimeable number, because it can be changed into a prime (1287640391) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 79 ways as a sum of consecutive naturals, for example, 1275651 + ... + 1276659.

It is an arithmetic number, because the mean of its divisors is an integer number (30356964).

It is a 1-persistent number, because it is pandigital, but 2⋅1287640395 = 2575280790 is not.

Almost surely, 2^1287640395 is an apocalyptic number.

1287640395 is a gapful number since it is divisible by the number (15) formed by its first and last digit.

1287640395 is a deficient number, since it is larger than the sum of its proper divisors (1140916725).

1287640395 is a wasteful number, since it uses less digits than its factorization.

1287640395 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1186 (or 1177 counting only the distinct ones).

The product of its (nonzero) digits is 362880, while the sum is 45.

The square root of 1287640395 is about 35883.7065393195. The cubic root of 1287640395 is about 1087.9230981523.

The spelling of 1287640395 in words is "one billion, two hundred eighty-seven million, six hundred forty thousand, three hundred ninety-five".