78639922 has 8 divisors (see below), whose sum is σ = 118017900. Its totient is φ = 39300624.

The previous prime is 78639889. The next prime is 78639923. The reversal of 78639922 is 22993687.

It can be written as a sum of positive squares in 2 ways, for example, as 69705801 + 8934121 = 8349^2 + 2989^2 .

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

It is not an unprimeable number, because it can be changed into a prime (78639923) 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, 3897 + ... + 13132.

Almost surely, 2^78639922 is an apocalyptic number.

78639922 is a deficient number, since it is larger than the sum of its proper divisors (39377978).

78639922 is a wasteful number, since it uses less digits than its factorization.

78639922 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 19340.

The product of its digits is 326592, while the sum is 46.

The square root of 78639922 is about 8867.9153130823. The cubic root of 78639922 is about 428.4311352756.

It can be divided in two parts, 78 and 639922, that added together give a square (640000 = 800²).

The spelling of 78639922 in words is "seventy-eight million, six hundred thirty-nine thousand, nine hundred twenty-two".