1265599878 has 16 divisors (see below), whose sum is σ = 2535593520. Its totient is φ = 421134336.

The previous prime is 1265599871. The next prime is 1265599889. The reversal of 1265599878 is 8789955621.

It is a super-2 number, since 2×1265599878² = 3203486102387229768, which contains 22 as substring.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1265599871) 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, 179323 + ... + 186246.

It is an arithmetic number, because the mean of its divisors is an integer number (158474595).

Almost surely, 2^1265599878 is an apocalyptic number.

1265599878 is an abundant number, since it is smaller than the sum of its proper divisors (1269993642).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

1265599878 is a wasteful number, since it uses less digits than its factorization.

1265599878 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 366151.

The product of its digits is 10886400, while the sum is 60.

The square root of 1265599878 is about 35575.2705963005. The cubic root of 1265599878 is about 1081.6800207067.

The spelling of 1265599878 in words is "one billion, two hundred sixty-five million, five hundred ninety-nine thousand, eight hundred seventy-eight".