1217878805 has 32 divisors (see below), whose sum is σ = 1753532928. Its totient is φ = 800179200.

The previous prime is 1217878757. The next prime is 1217878807. The reversal of 1217878805 is 5088787121.

1217878805 is digitally balanced in base 6, because in such base it contains all the possibile digits an equal number of times.

It is not a de Polignac number, because 1217878805 - 2¹⁰ = 1217877781 is a prime.

It is a Harshad number since it is a multiple of its sum of digits (47).

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 1217878805.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1217878807) by changing a digit.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 15485 + ... + 51725.

It is an arithmetic number, because the mean of its divisors is an integer number (54797904).

Almost surely, 2^1217878805 is an apocalyptic number.

It is an amenable number.

1217878805 is a deficient number, since it is larger than the sum of its proper divisors (535654123).

1217878805 is a wasteful number, since it uses less digits than its factorization.

1217878805 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 36317.

The product of its (nonzero) digits is 250880, while the sum is 47.

The square root of 1217878805 is about 34898.1203648563. The cubic root of 1217878805 is about 1067.9100922248.

The spelling of 1217878805 in words is "one billion, two hundred seventeen million, eight hundred seventy-eight thousand, eight hundred five".