78238381658 has 4 divisors (see below), whose sum is σ = 117357572490. Its totient is φ = 39119190828.

The previous prime is 78238381657. The next prime is 78238381691. The reversal of 78238381658 is 85618383287.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 85618383287 = 229 ⋅373879403.

It can be written as a sum of positive squares in only one way, i.e., 67421757649 + 10816624009 = 259657^2 + 104003^2 .

It is a super-2 number, since 2×78238381658² (a number of 23 digits) contains 22 as substring.

It is a junction number, because it is equal to n+sod(n) for n = 78238381597 and 78238381606.

It is not an unprimeable number, because it can be changed into a prime (78238381657) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 19559595413 + ... + 19559595416.

Almost surely, 2^78238381658 is an apocalyptic number.

78238381658 is a deficient number, since it is larger than the sum of its proper divisors (39119190832).

78238381658 is a wasteful number, since it uses less digits than its factorization.

78238381658 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 39119190831.

The product of its digits is 15482880, while the sum is 59.

The spelling of 78238381658 in words is "seventy-eight billion, two hundred thirty-eight million, three hundred eighty-one thousand, six hundred fifty-eight".