78663938 has 4 divisors (see below), whose sum is σ = 117995910. Its totient is φ = 39331968.

The previous prime is 78663931. The next prime is 78663941. The reversal of 78663938 is 83936687.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 83936687 = 163 ⋅514949.

It can be written as a sum of positive squares in only one way, i.e., 76860289 + 1803649 = 8767^2 + 1343^2 .

It is not an unprimeable number, because it can be changed into a prime (78663931) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 19665983 + ... + 19665986.

Almost surely, 2^78663938 is an apocalyptic number.

78663938 is a deficient number, since it is larger than the sum of its proper divisors (39331972).

78663938 is a wasteful number, since it uses less digits than its factorization.

78663938 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 39331971.

The product of its digits is 1306368, while the sum is 50.

The square root of 78663938 is about 8869.2693047398. The cubic root of 78663938 is about 428.4747439782.

The spelling of 78663938 in words is "seventy-eight million, six hundred sixty-three thousand, nine hundred thirty-eight".