77947 has 4 divisors (see below), whose sum is σ = 81360. Its totient is φ = 74536.

The previous prime is 77933. The next prime is 77951. The reversal of 77947 is 74977.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 74977 = 7 ⋅10711.

It is a cyclic number.

It is not a de Polignac number, because 77947 - 2¹⁵ = 45179 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (77977) 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, 1672 + ... + 1717.

It is an arithmetic number, because the mean of its divisors is an integer number (20340).

2⁷⁷⁹⁴⁷ is an apocalyptic number.

77947 is a deficient number, since it is larger than the sum of its proper divisors (3413).

77947 is a wasteful number, since it uses less digits than its factorization.

77947 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 3412.

The product of its digits is 12348, while the sum is 34.

The square root of 77947 is about 279.1898995308. The cubic root of 77947 is about 42.7169072349.

It can be divided in two parts, 77 and 947, that added together give a 10-th power (1024 = 2¹⁰).

The spelling of 77947 in words is "seventy-seven thousand, nine hundred forty-seven".