1640780459 has 4 divisors (see below), whose sum is σ = 1640911416. Its totient is φ = 1640649504.

The previous prime is 1640780447. The next prime is 1640780489. The reversal of 1640780459 is 9540870461.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 9540870461 = 12517 ⋅762233.

It is a cyclic number.

It is not a de Polignac number, because 1640780459 - 2⁸ = 1640780203 is a prime.

It is a Duffinian number.

It is a zygodrome in base 7.

It is not an unprimeable number, because it can be changed into a prime (1640780489) 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, 44429 + ... + 72494.

It is an arithmetic number, because the mean of its divisors is an integer number (410227854).

Almost surely, 2^1640780459 is an apocalyptic number.

1640780459 is a deficient number, since it is larger than the sum of its proper divisors (130957).

1640780459 is a wasteful number, since it uses less digits than its factorization.

1640780459 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 130956.

The product of its (nonzero) digits is 241920, while the sum is 44.

The square root of 1640780459 is about 40506.5483471500. The cubic root of 1640780459 is about 1179.4607463718.

The spelling of 1640780459 in words is "one billion, six hundred forty million, seven hundred eighty thousand, four hundred fifty-nine".