18641971 has 4 divisors (see below), whose sum is σ = 18650632. Its totient is φ = 18633312.

The previous prime is 18641963. The next prime is 18641977. The reversal of 18641971 is 17914681.

It is a semiprime because it is the product of two primes, and also a brilliant number, because the two primes have the same length, and also an emirpimes, since its reverse is a distinct semiprime: 17914681 = 113 ⋅158537.

It is a cyclic number.

It is not a de Polignac number, because 18641971 - 2³ = 18641963 is a prime.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 18641971.

It is not an unprimeable number, because it can be changed into a prime (18641977) 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, 1675 + ... + 6331.

It is an arithmetic number, because the mean of its divisors is an integer number (4662658).

Almost surely, 2^18641971 is an apocalyptic number.

18641971 is a deficient number, since it is larger than the sum of its proper divisors (8661).

18641971 is an equidigital number, since it uses as much as digits as its factorization.

18641971 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 8660.

The product of its digits is 12096, while the sum is 37.

The square root of 18641971 is about 4317.6348849804. The cubic root of 18641971 is about 265.1534461969.

The spelling of 18641971 in words is "eighteen million, six hundred forty-one thousand, nine hundred seventy-one".