16506423391 has 2 divisors, whose sum is σ = 16506423392. Its totient is φ = 16506423390.

The previous prime is 16506423389. The next prime is 16506423421. The reversal of 16506423391 is 19332460561.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 16506423391 - 2¹ = 16506423389 is a prime.

Together with 16506423389, it forms a pair of twin primes.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (16506423301) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 8253211695 + 8253211696.

It is an arithmetic number, because the mean of its divisors is an integer number (8253211696).

Almost surely, 2^16506423391 is an apocalyptic number.

16506423391 is a deficient number, since it is larger than the sum of its proper divisors (1).

16506423391 is an equidigital number, since it uses as much as digits as its factorization.

16506423391 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 116640, while the sum is 40.

The spelling of 16506423391 in words is "sixteen billion, five hundred six million, four hundred twenty-three thousand, three hundred ninety-one".