78634 has 4 divisors (see below), whose sum is σ = 117954. Its totient is φ = 39316.

The previous prime is 78623. The next prime is 78643. The reversal of 78634 is 43687.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in only one way, i.e., 55225 + 23409 = 235^2 + 153^2 .

It is an Ulam number.

It is an unprimeable number.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 19657 + ... + 19660.

2⁷⁸⁶³⁴ is an apocalyptic number.

78634 is a deficient number, since it is larger than the sum of its proper divisors (39320).

78634 is a wasteful number, since it uses less digits than its factorization.

78634 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 39319.

The product of its digits is 4032, while the sum is 28.

The square root of 78634 is about 280.4175458134. The cubic root of 78634 is about 42.8420380633.

Subtracting from 78634 its sum of digits (28), we obtain a triangular number (78606 = T₃₉₆).

It can be divided in two parts, 786 and 34, that added together give a triangular number (820 = T₄₀).

The spelling of 78634 in words is "seventy-eight thousand, six hundred thirty-four".