18727481 has 2 divisors, whose sum is σ = 18727482. Its totient is φ = 18727480.

The previous prime is 18727477. The next prime is 18727531. The reversal of 18727481 is 18472781.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 18567481 + 160000 = 4309^2 + 400^2 .

It is an emirp because it is prime and its reverse (18472781) is a distict prime.

It is a cyclic number.

It is not a de Polignac number, because 18727481 - 2² = 18727477 is a prime.

It is a super-3 number, since 3×18727481³ (a number of 23 digits) contains 333 as substring. Note that it is a super-d number also for d = 2.

It is a Chen prime.

It is not a weakly prime, because it can be changed into another prime (18727781) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 9363740 + 9363741.

It is an arithmetic number, because the mean of its divisors is an integer number (9363741).

Almost surely, 2^18727481 is an apocalyptic number.

It is an amenable number.

18727481 is a deficient number, since it is larger than the sum of its proper divisors (1).

18727481 is an equidigital number, since it uses as much as digits as its factorization.

18727481 is an evil number, because the sum of its binary digits is even.

The product of its digits is 25088, while the sum is 38.

The square root of 18727481 is about 4327.5259675708. The cubic root of 18727481 is about 265.5582440965.

The spelling of 18727481 in words is "eighteen million, seven hundred twenty-seven thousand, four hundred eighty-one".