123456778919 has 4 divisors (see below), whose sum is σ = 126083518944. Its totient is φ = 120830038896.

The previous prime is 123456778901. The next prime is 123456778981. The reversal of 123456778919 is 919877654321.

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

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-123456778919 is a prime.

It is a super-2 number, since 2×123456778919² (a number of 23 digits) contains 22 as substring.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (123456378919) 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, 1313369942 + ... + 1313370035.

It is an arithmetic number, because the mean of its divisors is an integer number (31520879736).

Almost surely, 2^123456778919 is an apocalyptic number.

123456778919 is a deficient number, since it is larger than the sum of its proper divisors (2626740025).

123456778919 is an equidigital number, since it uses as much as digits as its factorization.

123456778919 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2626740024.

The product of its digits is 22861440, while the sum is 62.

The spelling of 123456778919 in words is "one hundred twenty-three billion, four hundred fifty-six million, seven hundred seventy-eight thousand, nine hundred nineteen".