18391716 has 72 divisors (see below), whose sum is σ = 54075840. Its totient is φ = 5161536.

The previous prime is 18391699. The next prime is 18391717. The reversal of 18391716 is 61719381.

It is a Harshad number since it is a multiple of its sum of digits (36).

It is not an unprimeable number, because it can be changed into a prime (18391717) by changing a digit.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 14250 + ... + 15486.

Almost surely, 2^18391716 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 18391716, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (27037920).

18391716 is an abundant number, since it is smaller than the sum of its proper divisors (35684124).

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

18391716 is a wasteful number, since it uses less digits than its factorization.

18391716 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1313 (or 1308 counting only the distinct ones).

The product of its digits is 9072, while the sum is 36.

The square root of 18391716 is about 4288.5564004686. The cubic root of 18391716 is about 263.9615990977.

The spelling of 18391716 in words is "eighteen million, three hundred ninety-one thousand, seven hundred sixteen".