780287009 has 4 divisors (see below), whose sum is σ = 780550020. Its totient is φ = 780024000.

The previous prime is 780286979. The next prime is 780287033. The reversal of 780287009 is 900782087.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 900782087 = 59 ⋅15267493.

It can be written as a sum of positive squares in 2 ways, for example, as 191739409 + 588547600 = 13847^2 + 24260^2 .

It is a cyclic number.

It is not a de Polignac number, because 780287009 - 2²⁰ = 779238433 is a prime.

It is a Duffinian number.

It is a Curzon number.

It is not an unprimeable number, because it can be changed into a prime (780287069) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 127004 + ... + 133005.

It is an arithmetic number, because the mean of its divisors is an integer number (195137505).

Almost surely, 2^780287009 is an apocalyptic number.

It is an amenable number.

780287009 is a deficient number, since it is larger than the sum of its proper divisors (263011).

780287009 is a wasteful number, since it uses less digits than its factorization.

780287009 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 263010.

The product of its (nonzero) digits is 56448, while the sum is 41.

The square root of 780287009 is about 27933.6179003007. The cubic root of 780287009 is about 920.6292988908.

The spelling of 780287009 in words is "seven hundred eighty million, two hundred eighty-seven thousand, nine".