1278865215 has 24 divisors (see below), whose sum is σ = 2218338720. Its totient is φ = 681557184.

The previous prime is 1278865213. The next prime is 1278865241. The reversal of 1278865215 is 5125688721.

It is not a de Polignac number, because 1278865215 - 2¹ = 1278865213 is a prime.

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

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1278865213) by changing a digit.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 55606 + ... + 75164.

It is an arithmetic number, because the mean of its divisors is an integer number (92430780).

Almost surely, 2^1278865215 is an apocalyptic number.

1278865215 is a gapful number since it is divisible by the number (15) formed by its first and last digit.

1278865215 is a deficient number, since it is larger than the sum of its proper divisors (939473505).

1278865215 is a wasteful number, since it uses less digits than its factorization.

1278865215 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 21023 (or 21020 counting only the distinct ones).

The product of its digits is 268800, while the sum is 45.

The square root of 1278865215 is about 35761.2250209637. The cubic root of 1278865215 is about 1085.4460892298.

The spelling of 1278865215 in words is "one billion, two hundred seventy-eight million, eight hundred sixty-five thousand, two hundred fifteen".