18632881 has 2 divisors, whose sum is σ = 18632882. Its totient is φ = 18632880.

The previous prime is 18632879. The next prime is 18632899. The reversal of 18632881 is 18823681.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 18533025 + 99856 = 4305^2 + 316^2 .

It is an emirp because it is prime and its reverse (18823681) is a distict prime.

It is a cyclic number.

It is not a de Polignac number, because 18632881 - 2¹ = 18632879 is a prime.

It is a super-2 number, since 2×18632881² = 694368508720322, which contains 22 as substring.

Together with 18632879, it forms a pair of twin primes.

It is a self number, because there is not a number n which added to its sum of digits gives 18632881.

It is not a weakly prime, because it can be changed into another prime (18632381) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 9316440 + 9316441.

It is an arithmetic number, because the mean of its divisors is an integer number (9316441).

Almost surely, 2^18632881 is an apocalyptic number.

It is an amenable number.

18632881 is a deficient number, since it is larger than the sum of its proper divisors (1).

18632881 is an equidigital number, since it uses as much as digits as its factorization.

18632881 is an evil number, because the sum of its binary digits is even.

The product of its digits is 18432, while the sum is 37.

The square root of 18632881 is about 4316.5820969837. The cubic root of 18632881 is about 265.1103420873.

The spelling of 18632881 in words is "eighteen million, six hundred thirty-two thousand, eight hundred eighty-one".