18991030 has 16 divisors (see below), whose sum is σ = 34524144. Its totient is φ = 7520800.

The previous prime is 18991019. The next prime is 18991033. The reversal of 18991030 is 3019981.

It is a junction number, because it is equal to n+sod(n) for n = 18990983 and 18991001.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (18991033) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 8392 + ... + 10411.

It is an arithmetic number, because the mean of its divisors is an integer number (2157759).

Almost surely, 2^18991030 is an apocalyptic number.

18991030 is a gapful number since it is divisible by the number (10) formed by its first and last digit.

18991030 is a deficient number, since it is larger than the sum of its proper divisors (15533114).

18991030 is a wasteful number, since it uses less digits than its factorization.

18991030 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 18911.

The product of its (nonzero) digits is 1944, while the sum is 31.

The square root of 18991030 is about 4357.8698925048. The cubic root of 18991030 is about 266.7981660468.

It can be divided in two parts, 189 and 91030, that added together give a palindrome (91219).

The spelling of 18991030 in words is "eighteen million, nine hundred ninety-one thousand, thirty".