19518494951 has 4 divisors (see below), whose sum is σ = 19567169904. Its totient is φ = 19469820000.

The previous prime is 19518494929. The next prime is 19518494993. The reversal of 19518494951 is 15949481591.

It is a happy number.

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-19518494951 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (19518494351) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 24336875 + ... + 24337676.

It is an arithmetic number, because the mean of its divisors is an integer number (4891792476).

Almost surely, 2^19518494951 is an apocalyptic number.

19518494951 is a deficient number, since it is larger than the sum of its proper divisors (48674953).

19518494951 is an equidigital number, since it uses as much as digits as its factorization.

19518494951 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 48674952.

The product of its digits is 2332800, while the sum is 56.

The spelling of 19518494951 in words is "nineteen billion, five hundred eighteen million, four hundred ninety-four thousand, nine hundred fifty-one".