18813481 has 2 divisors, whose sum is σ = 18813482. Its totient is φ = 18813480.

The previous prime is 18813479. The next prime is 18813539. The reversal of 18813481 is 18431881.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 15872256 + 2941225 = 3984^2 + 1715^2 .

It is a cyclic number.

It is not a de Polignac number, because 18813481 - 2¹ = 18813479 is a prime.

It is a super-2 number, since 2×18813481² = 707894134674722, which contains 22 as substring.

Together with 18813479, it forms a pair of twin primes.

It is not a weakly prime, because it can be changed into another prime (18813451) 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, 9406740 + 9406741.

It is an arithmetic number, because the mean of its divisors is an integer number (9406741).

Almost surely, 2^18813481 is an apocalyptic number.

It is an amenable number.

18813481 is a deficient number, since it is larger than the sum of its proper divisors (1).

18813481 is an equidigital number, since it uses as much as digits as its factorization.

18813481 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 6144, while the sum is 34.

The square root of 18813481 is about 4337.4509795501. The cubic root of 18813481 is about 265.9641207001.

The spelling of 18813481 in words is "eighteen million, eight hundred thirteen thousand, four hundred eighty-one".