77819409 has 12 divisors (see below), whose sum is σ = 112491652. Its totient is φ = 51840000.

The previous prime is 77819381. The next prime is 77819411. The reversal of 77819409 is 90491877.

It can be written as a sum of positive squares in 2 ways, for example, as 25979409 + 51840000 = 5097^2 + 7200^2 .

It is not a de Polignac number, because 77819409 - 2¹¹ = 77817361 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (77819449) by changing a digit.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 13809 + ... + 18609.

Almost surely, 2^77819409 is an apocalyptic number.

It is an amenable number.

77819409 is a deficient number, since it is larger than the sum of its proper divisors (34672243).

77819409 is a wasteful number, since it uses less digits than its factorization.

77819409 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 6608 (or 6605 counting only the distinct ones).

The product of its (nonzero) digits is 127008, while the sum is 45.

The square root of 77819409 is about 8821.5309895732. The cubic root of 77819409 is about 426.9358681864.

The spelling of 77819409 in words is "seventy-seven million, eight hundred nineteen thousand, four hundred nine".