18981731 has 2 divisors, whose sum is σ = 18981732. Its totient is φ = 18981730.

The previous prime is 18981727. The next prime is 18981751. The reversal of 18981731 is 13718981.

It is a weak prime.

It is an emirp because it is prime and its reverse (13718981) is a distict prime.

It is a cyclic number.

It is not a de Polignac number, because 18981731 - 2² = 18981727 is a prime.

It is a super-2 number, since 2×18981731² = 720612223512722, which contains 22 as substring.

It is a Chen prime.

It is not a weakly prime, because it can be changed into another prime (18981751) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 9490865 + 9490866.

It is an arithmetic number, because the mean of its divisors is an integer number (9490866).

Almost surely, 2^18981731 is an apocalyptic number.

18981731 is a deficient number, since it is larger than the sum of its proper divisors (1).

18981731 is an equidigital number, since it uses as much as digits as its factorization.

18981731 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 12096, while the sum is 38.

The square root of 18981731 is about 4356.8028415341. The cubic root of 18981731 is about 266.7546128326.

The spelling of 18981731 in words is "eighteen million, nine hundred eighty-one thousand, seven hundred thirty-one".