77878390489 has 9 divisors (see below), whose sum is σ = 80664836863. Its totient is φ = 75185114872.

The previous prime is 77878390487. The next prime is 77878390519. The reversal of 77878390489 is 98409387877.

The square root of 77878390489 is 279067.

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., 40837538889 + 37040851600 = 202083^2 + 192460^2 .

It is not a de Polignac number, because 77878390489 - 2¹ = 77878390487 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (77878390487) 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, 8088132 + ... + 8097754.

Almost surely, 2^77878390489 is an apocalyptic number.

77878390489 is the 279067-th square number.

77878390489 is the 139534-th centered octagonal number.

It is an amenable number.

77878390489 is a deficient number, since it is larger than the sum of its proper divisors (2786446374).

77878390489 is an frugal number, since it uses more digits than its factorization.

77878390489 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 19304 (or 9652 counting only the distinct ones).

The product of its (nonzero) digits is 170698752, while the sum is 70.

The spelling of 77878390489 in words is "seventy-seven billion, eight hundred seventy-eight million, three hundred ninety thousand, four hundred eighty-nine".