18421716 has 48 divisors (see below), whose sum is σ = 46323200. Its totient is φ = 5679072.

The previous prime is 18421709. The next prime is 18421721. The reversal of 18421716 is 61712481.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 8865 + ... + 10743.

Almost surely, 2^18421716 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 18421716, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (23161600).

18421716 is an abundant number, since it is smaller than the sum of its proper divisors (27901484).

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

18421716 is a wasteful number, since it uses less digits than its factorization.

18421716 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1948 (or 1946 counting only the distinct ones).

The product of its digits is 2688, while the sum is 30.

The square root of 18421716 is about 4292.0526557814. The cubic root of 18421716 is about 264.1050431391.

The spelling of 18421716 in words is "eighteen million, four hundred twenty-one thousand, seven hundred sixteen".