18991446 has 16 divisors (see below), whose sum is σ = 38909808. Its totient is φ = 6176000.

The previous prime is 18991439. The next prime is 18991457. The reversal of 18991446 is 64419981.

It is a junction number, because it is equal to n+sod(n) for n = 18991398 and 18991407.

It is a congruent number.

It is an unprimeable number.

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 7 ways as a sum of consecutive naturals, for example, 38355 + ... + 38846.

It is an arithmetic number, because the mean of its divisors is an integer number (2431863).

Almost surely, 2^18991446 is an apocalyptic number.

18991446 is an abundant number, since it is smaller than the sum of its proper divisors (19918362).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

18991446 is a wasteful number, since it uses less digits than its factorization.

18991446 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 77247.

The product of its digits is 62208, while the sum is 42.

The square root of 18991446 is about 4357.9176219842. The cubic root of 18991446 is about 266.8001141108.

The spelling of 18991446 in words is "eighteen million, nine hundred ninety-one thousand, four hundred forty-six".