18721072 has 10 divisors (see below), whose sum is σ = 36272108. Its totient is φ = 9360528.

The previous prime is 18721033. The next prime is 18721091. The reversal of 18721072 is 27012781.

It is an alternating number because its digits alternate between odd and even.

It is a self number, because there is not a number n which added to its sum of digits gives 18721072.

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 as a sum of consecutive naturals, namely, 585018 + ... + 585049.

Almost surely, 2^18721072 is an apocalyptic number.

It is an amenable number.

18721072 is a deficient number, since it is larger than the sum of its proper divisors (17551036).

18721072 is a wasteful number, since it uses less digits than its factorization.

18721072 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1170075 (or 1170069 counting only the distinct ones).

The product of its (nonzero) digits is 1568, while the sum is 28.

The square root of 18721072 is about 4326.7854118271. The cubic root of 18721072 is about 265.5279471410.

The spelling of 18721072 in words is "eighteen million, seven hundred twenty-one thousand, seventy-two".