18981071 has 4 divisors (see below), whose sum is σ = 18994752. Its totient is φ = 18967392.

The previous prime is 18981047. The next prime is 18981077. The reversal of 18981071 is 17018981.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 17018981 = 7 ⋅2431283.

It is a cyclic number.

It is not a de Polignac number, because 18981071 - 2¹⁰ = 18980047 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (18981077) 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 in 3 ways as a sum of consecutive naturals, for example, 4490 + ... + 7623.

It is an arithmetic number, because the mean of its divisors is an integer number (4748688).

Almost surely, 2^18981071 is an apocalyptic number.

18981071 is a deficient number, since it is larger than the sum of its proper divisors (13681).

18981071 is a wasteful number, since it uses less digits than its factorization.

18981071 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 13680.

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

The square root of 18981071 is about 4356.7270972601. The cubic root of 18981071 is about 266.7515210864.

The spelling of 18981071 in words is "eighteen million, nine hundred eighty-one thousand, seventy-one".