83779565809 has 9 divisors (see below), whose sum is σ = 86578584651. Its totient is φ = 81068315760.

The previous prime is 83779565783. The next prime is 83779565851. The reversal of 83779565809 is 90856597738.

The square root of 83779565809 is 289447.

It is a perfect power (a square), and thus also a powerful number.

It can be written as a sum of positive squares in only one way, i.e., 79492983025 + 4286582784 = 281945^2 + 65472^2 .

It is not a de Polignac number, because 83779565809 - 2⁹ = 83779565297 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (83779565209) by changing a digit.

It is a polite number, since it can be written in 8 ways as a sum of consecutive naturals, for example, 8968189 + ... + 8977525.

It is an arithmetic number, because the mean of its divisors is an integer number (9619842739).

Almost surely, 2^83779565809 is an apocalyptic number.

83779565809 is the 289447-th square number.

83779565809 is the 144724-th centered octagonal number.

It is an amenable number.

83779565809 is a deficient number, since it is larger than the sum of its proper divisors (2799018842).

83779565809 is an frugal number, since it uses more digits than its factorization.

83779565809 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 18736 (or 9368 counting only the distinct ones).

The product of its (nonzero) digits is 114307200, while the sum is 67.

The spelling of 83779565809 in words is "eighty-three billion, seven hundred seventy-nine million, five hundred sixty-five thousand, eight hundred nine".