78138191949 has 4 divisors (see below), whose sum is σ = 104184255936. Its totient is φ = 52092127964.

The previous prime is 78138191933. The next prime is 78138191953. The reversal of 78138191949 is 94919183187.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is a cyclic number.

It is not a de Polignac number, because 78138191949 - 2⁴ = 78138191933 is a prime.

It is a super-2 number, since 2×78138191949² (a number of 23 digits) contains 22 as substring.

It is a junction number, because it is equal to n+sod(n) for n = 78138191892 and 78138191901.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (78138191959) 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, 13023031989 + ... + 13023031994.

It is an arithmetic number, because the mean of its divisors is an integer number (26046063984).

Almost surely, 2^78138191949 is an apocalyptic number.

It is an amenable number.

78138191949 is a deficient number, since it is larger than the sum of its proper divisors (26046063987).

78138191949 is a wasteful number, since it uses less digits than its factorization.

78138191949 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 26046063986.

The product of its digits is 3919104, while the sum is 60.

The spelling of 78138191949 in words is "seventy-eight billion, one hundred thirty-eight million, one hundred ninety-one thousand, nine hundred forty-nine".