1780320065 has 4 divisors (see below), whose sum is σ = 2136384084. Its totient is φ = 1424256048.

The previous prime is 1780320043. The next prime is 1780320077. The reversal of 1780320065 is 5600230871.

It is a happy number.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 1079976769 + 700343296 = 32863^2 + 26464^2 .

It is a cyclic number.

It is not a de Polignac number, because 1780320065 - 2²⁰ = 1779271489 is a prime.

It is a Duffinian number.

It is an unprimeable number.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 178032002 + ... + 178032011.

It is an arithmetic number, because the mean of its divisors is an integer number (534096021).

Almost surely, 2^1780320065 is an apocalyptic number.

It is an amenable number.

1780320065 is a deficient number, since it is larger than the sum of its proper divisors (356064019).

1780320065 is an equidigital number, since it uses as much as digits as its factorization.

1780320065 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 356064018.

The product of its (nonzero) digits is 10080, while the sum is 32.

The square root of 1780320065 is about 42193.8391829897. The cubic root of 1780320065 is about 1211.9909088206.

The spelling of 1780320065 in words is "one billion, seven hundred eighty million, three hundred twenty thousand, sixty-five".