78790405669 has 4 divisors (see below), whose sum is σ = 78822268396. Its totient is φ = 78758542944.

The previous prime is 78790405657. The next prime is 78790405679. The reversal of 78790405669 is 96650409787.

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 40134913569 + 38655492100 = 200337^2 + 196610^2 .

It is a cyclic number.

It is not a de Polignac number, because 78790405669 - 2²¹ = 78788308517 is a prime.

It is a super-2 number, since 2×78790405669² (a number of 23 digits) contains 22 as substring.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (78790405609) 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, 15927654 + ... + 15932599.

It is an arithmetic number, because the mean of its divisors is an integer number (19705567099).

Almost surely, 2^78790405669 is an apocalyptic number.

It is an amenable number.

78790405669 is a deficient number, since it is larger than the sum of its proper divisors (31862727).

78790405669 is a wasteful number, since it uses less digits than its factorization.

78790405669 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 31862726.

The product of its (nonzero) digits is 22861440, while the sum is 61.

The spelling of 78790405669 in words is "seventy-eight billion, seven hundred ninety million, four hundred five thousand, six hundred sixty-nine".