18991375451 has 2 divisors, whose sum is σ = 18991375452. Its totient is φ = 18991375450.

The previous prime is 18991375411. The next prime is 18991375453. The reversal of 18991375451 is 15457319981.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 18991375451 - 2¹⁴ = 18991359067 is a prime.

It is a Sophie Germain prime.

Together with 18991375453, it forms a pair of twin primes.

It is a Chen prime.

It is a junction number, because it is equal to n+sod(n) for n = 18991375393 and 18991375402.

It is not a weakly prime, because it can be changed into another prime (18991375453) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 9495687725 + 9495687726.

It is an arithmetic number, because the mean of its divisors is an integer number (9495687726).

Almost surely, 2^18991375451 is an apocalyptic number.

18991375451 is a deficient number, since it is larger than the sum of its proper divisors (1).

18991375451 is an equidigital number, since it uses as much as digits as its factorization.

18991375451 is an evil number, because the sum of its binary digits is even.

The product of its digits is 1360800, while the sum is 53.

The spelling of 18991375451 in words is "eighteen billion, nine hundred ninety-one million, three hundred seventy-five thousand, four hundred fifty-one".