77781385 has 8 divisors (see below), whose sum is σ = 101822976. Its totient is φ = 56568240.

The previous prime is 77781373. The next prime is 77781391. The reversal of 77781385 is 58318777.

It is a happy number.

It is a sphenic number, since it is the product of 3 distinct primes.

It is not a de Polignac number, because 77781385 - 2⁷ = 77781257 is a prime.

It is a Duffinian number.

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 707049 + ... + 707158.

It is an arithmetic number, because the mean of its divisors is an integer number (12727872).

Almost surely, 2^77781385 is an apocalyptic number.

It is an amenable number.

77781385 is a deficient number, since it is larger than the sum of its proper divisors (24041591).

77781385 is a wasteful number, since it uses less digits than its factorization.

77781385 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1414223.

The product of its digits is 329280, while the sum is 46.

The square root of 77781385 is about 8819.3755447877. The cubic root of 77781385 is about 426.8663206085.

The spelling of 77781385 in words is "seventy-seven million, seven hundred eighty-one thousand, three hundred eighty-five".