18971081 has 4 divisors (see below), whose sum is σ = 19087632. Its totient is φ = 18854532.

The previous prime is 18971059. The next prime is 18971083. The reversal of 18971081 is 18017981.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is a cyclic number.

It is not a de Polignac number, because 18971081 - 2¹⁰ = 18970057 is a prime.

It is a super-2 number, since 2×18971081² = 719803828617122, which contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (18971083) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 58031 + ... + 58356.

It is an arithmetic number, because the mean of its divisors is an integer number (4771908).

Almost surely, 2^18971081 is an apocalyptic number.

It is an amenable number.

18971081 is a deficient number, since it is larger than the sum of its proper divisors (116551).

18971081 is a wasteful number, since it uses less digits than its factorization.

18971081 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 116550.

The product of its (nonzero) digits is 4032, while the sum is 35.

The square root of 18971081 is about 4355.5804435230. The cubic root of 18971081 is about 266.7047145364.

The spelling of 18971081 in words is "eighteen million, nine hundred seventy-one thousand, eighty-one".