18721612 has 48 divisors (see below), whose sum is σ = 42461440. Its totient is φ = 7013952.

The previous prime is 18721601. The next prime is 18721627. The reversal of 18721612 is 21612781.

It is a Harshad number since it is a multiple of its sum of digits (28).

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

It is an unprimeable number.

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 15 ways as a sum of consecutive naturals, for example, 5563 + ... + 8269.

Almost surely, 2^18721612 is an apocalyptic number.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 18721612, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (21230720).

18721612 is an abundant number, since it is smaller than the sum of its proper divisors (23739828).

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

18721612 is a wasteful number, since it uses less digits than its factorization.

18721612 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2750 (or 2748 counting only the distinct ones).

The product of its digits is 1344, while the sum is 28.

The square root of 18721612 is about 4326.8478133625. The cubic root of 18721612 is about 265.5305001236.

The spelling of 18721612 in words is "eighteen million, seven hundred twenty-one thousand, six hundred twelve".