18739691 has 2 divisors, whose sum is σ = 18739692. Its totient is φ = 18739690.

The previous prime is 18739667. The next prime is 18739697. The reversal of 18739691 is 19693781.

It is a strong prime.

It is an emirp because it is prime and its reverse (19693781) is a distict prime.

It is a cyclic number.

It is not a de Polignac number, because 18739691 - 2¹⁰ = 18738667 is a prime.

It is a Chen prime.

It is not a weakly prime, because it can be changed into another prime (18739697) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 9369845 + 9369846.

It is an arithmetic number, because the mean of its divisors is an integer number (9369846).

Almost surely, 2^18739691 is an apocalyptic number.

18739691 is a deficient number, since it is larger than the sum of its proper divisors (1).

18739691 is an equidigital number, since it uses as much as digits as its factorization.

18739691 is an evil number, because the sum of its binary digits is even.

The product of its digits is 81648, while the sum is 44.

The square root of 18739691 is about 4328.9364744704. The cubic root of 18739691 is about 265.6159447155.

The spelling of 18739691 in words is "eighteen million, seven hundred thirty-nine thousand, six hundred ninety-one".