1265780385 has 32 divisors (see below), whose sum is σ = 2254250880. Its totient is φ = 673890624.

The previous prime is 1265780381. The next prime is 1265780387. The reversal of 1265780385 is 5830875621.

1265780385 is a `hidden beast` number, since 1 + 265 + 7 + 8 + 0 + 385 = 666.

It is not a de Polignac number, because 1265780385 - 2² = 1265780381 is a prime.

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

It is a self number, because there is not a number n which added to its sum of digits gives 1265780385.

It is not an unprimeable number, because it can be changed into a prime (1265780381) 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, 71259 + ... + 87231.

It is an arithmetic number, because the mean of its divisors is an integer number (70445340).

Almost surely, 2^1265780385 is an apocalyptic number.

1265780385 is a gapful number since it is divisible by the number (15) formed by its first and last digit.

It is an amenable number.

1265780385 is a deficient number, since it is larger than the sum of its proper divisors (988470495).

1265780385 is a wasteful number, since it uses less digits than its factorization.

1265780385 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 16574 (or 16568 counting only the distinct ones).

The product of its (nonzero) digits is 403200, while the sum is 45.

The square root of 1265780385 is about 35577.8074788203. The cubic root of 1265780385 is about 1081.7314433659.

The spelling of 1265780385 in words is "one billion, two hundred sixty-five million, seven hundred eighty thousand, three hundred eighty-five".