18817481 has 2 divisors, whose sum is σ = 18817482. Its totient is φ = 18817480.

The previous prime is 18817439. The next prime is 18817489. The reversal of 18817481 is 18471881.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 18567481 + 250000 = 4309^2 + 500^2 .

It is an emirp because it is prime and its reverse (18471881) is a distict prime.

It is a cyclic number.

It is not a de Polignac number, because 18817481 - 2⁶ = 18817417 is a prime.

It is a super-2 number, since 2×18817481² = 708195182370722, which contains 22 as substring.

It is a Chen prime.

It is not a weakly prime, because it can be changed into another prime (18817489) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 9408740 + 9408741.

It is an arithmetic number, because the mean of its divisors is an integer number (9408741).

Almost surely, 2^18817481 is an apocalyptic number.

It is an amenable number.

18817481 is a deficient number, since it is larger than the sum of its proper divisors (1).

18817481 is an equidigital number, since it uses as much as digits as its factorization.

18817481 is an evil number, because the sum of its binary digits is even.

The product of its digits is 14336, while the sum is 38.

The square root of 18817481 is about 4337.9120553557. The cubic root of 18817481 is about 265.9829685517.

The spelling of 18817481 in words is "eighteen million, eight hundred seventeen thousand, four hundred eighty-one".