1288779891 has 8 divisors (see below), whose sum is σ = 1963855104. Its totient is φ = 736445640.

The previous prime is 1288779883. The next prime is 1288779917. The reversal of 1288779891 is 1989778821.

It is a sphenic number, since it is the product of 3 distinct primes.

It is not a de Polignac number, because 1288779891 - 2³ = 1288779883 is a prime.

It is not an unprimeable number, because it can be changed into a prime (1288779881) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 30685215 + ... + 30685256.

It is an arithmetic number, because the mean of its divisors is an integer number (245481888).

Almost surely, 2^1288779891 is an apocalyptic number.

1288779891 is a deficient number, since it is larger than the sum of its proper divisors (675075213).

1288779891 is an equidigital number, since it uses as much as digits as its factorization.

1288779891 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 61370481.

The product of its digits is 4064256, while the sum is 60.

The square root of 1288779891 is about 35899.5806521469. The cubic root of 1288779891 is about 1088.2439223300.

The spelling of 1288779891 in words is "one billion, two hundred eighty-eight million, seven hundred seventy-nine thousand, eight hundred ninety-one".