80778166405 has 16 divisors (see below), whose sum is σ = 97646022000. Its totient is φ = 64148267520.

The previous prime is 80778166397. The next prime is 80778166451. The reversal of 80778166405 is 50466187708.

It can be written as a sum of positive squares in 8 ways, for example, as 2743978689 + 78034187716 = 52383^2 + 279346^2 .

It is not a de Polignac number, because 80778166405 - 2³ = 80778166397 is a prime.

It is a super-2 number, since 2×80778166405² (a number of 23 digits) contains 22 as substring.

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 1174201 + ... + 1241089.

It is an arithmetic number, because the mean of its divisors is an integer number (6102876375).

Almost surely, 2^80778166405 is an apocalyptic number.

It is an amenable number.

80778166405 is a deficient number, since it is larger than the sum of its proper divisors (16867855595).

80778166405 is a wasteful number, since it uses less digits than its factorization.

80778166405 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 68664.

The product of its (nonzero) digits is 2257920, while the sum is 52.

The spelling of 80778166405 in words is "eighty billion, seven hundred seventy-eight million, one hundred sixty-six thousand, four hundred five".