18811642 has 4 divisors (see below), whose sum is σ = 28217466. Its totient is φ = 9405820.

The previous prime is 18811627. The next prime is 18811643. The reversal of 18811642 is 24611881.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in only one way, i.e., 10569001 + 8242641 = 3251^2 + 2871^2 .

It is a Smith number, since the sum of its digits (31) coincides with the sum of the digits of its prime factors. Since it is squarefree, it is also a hoax number.

It is not an unprimeable number, because it can be changed into a prime (18811643) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 4702909 + ... + 4702912.

Almost surely, 2^18811642 is an apocalyptic number.

18811642 is a deficient number, since it is larger than the sum of its proper divisors (9405824).

18811642 is an equidigital number, since it uses as much as digits as its factorization.

18811642 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 9405823.

The product of its digits is 3072, while the sum is 31.

The square root of 18811642 is about 4337.2389835009. The cubic root of 18811642 is about 265.9554545038.

The spelling of 18811642 in words is "eighteen million, eight hundred eleven thousand, six hundred forty-two".