1278428287 has 4 divisors (see below), whose sum is σ = 1279429120. Its totient is φ = 1277427456.

The previous prime is 1278428279. The next prime is 1278428293. The reversal of 1278428287 is 7828248721.

It is a happy number.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 7828248721 = 107 ⋅73161203.

It is a cyclic number.

It is not a de Polignac number, because 1278428287 - 2³ = 1278428279 is a prime.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 1278428287.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1278425287) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 498498 + ... + 501055.

It is an arithmetic number, because the mean of its divisors is an integer number (319857280).

Almost surely, 2^1278428287 is an apocalyptic number.

1278428287 is a deficient number, since it is larger than the sum of its proper divisors (1000833).

1278428287 is an equidigital number, since it uses as much as digits as its factorization.

1278428287 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1000832.

The product of its digits is 802816, while the sum is 49.

The square root of 1278428287 is about 35755.1155361020. The cubic root of 1278428287 is about 1085.3224598839.

The spelling of 1278428287 in words is "one billion, two hundred seventy-eight million, four hundred twenty-eight thousand, two hundred eighty-seven".