18471881 has 2 divisors, whose sum is σ = 18471882. Its totient is φ = 18471880.

The previous prime is 18471863. The next prime is 18471889. The reversal of 18471881 is 18817481.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 17774656 + 697225 = 4216^2 + 835^2 .

It is an emirp because it is prime and its reverse (18817481) is a distict prime.

It is a cyclic number.

It is not a de Polignac number, because 18471881 - 2¹⁴ = 18455497 is a prime.

It is a super-2 number, since 2×18471881² = 682420775356322, which contains 22 as substring.

It is a Sophie Germain prime.

It is a Chen prime.

It is a Curzon number.

It is not a weakly prime, because it can be changed into another prime (18471889) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 9235940 + 9235941.

It is an arithmetic number, because the mean of its divisors is an integer number (9235941).

Almost surely, 2^18471881 is an apocalyptic number.

It is an amenable number.

18471881 is a deficient number, since it is larger than the sum of its proper divisors (1).

18471881 is an equidigital number, since it uses as much as digits as its factorization.

18471881 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 18471881 is about 4297.8926231352. The cubic root of 18471881 is about 264.3445579503.

The spelling of 18471881 in words is "eighteen million, four hundred seventy-one thousand, eight hundred eighty-one".