77428 has 12 divisors (see below), whose sum is σ = 146020. Its totient is φ = 35712.

The previous prime is 77419. The next prime is 77431. The reversal of 77428 is 82477.

77428 is nontrivially palindromic in base 3.

It can be written as a sum of positive squares in 2 ways, for example, as 13924 + 63504 = 118^2 + 252^2 .

It is a hoax number, since the sum of its digits (28) coincides with the sum of the digits of its distinct prime factors.

It is a junction number, because it is equal to n+sod(n) for n = 77396 and 77405.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 693 + ... + 796.

2⁷⁷⁴²⁸ is an apocalyptic number.

It is an amenable number.

77428 is a deficient number, since it is larger than the sum of its proper divisors (68592).

77428 is a wasteful number, since it uses less digits than its factorization.

77428 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1506 (or 1504 counting only the distinct ones).

The product of its digits is 3136, while the sum is 28.

The square root of 77428 is about 278.2588722754. The cubic root of 77428 is about 42.6218876994.

It can be divided in two parts, 7742 and 8, that added together give a triangular number (7750 = T₁₂₄).

The spelling of 77428 in words is "seventy-seven thousand, four hundred twenty-eight".