18012720 has 80 divisors (see below), whose sum is σ = 60924672. Its totient is φ = 4366080.

The previous prime is 18012719. The next prime is 18012721. The reversal of 18012720 is 2721081.

It is an interprime number because it is at equal distance from previous prime (18012719) and next prime (18012721).

It is a tau number, because it is divible by the number of its divisors (80).

It is not an unprimeable number, because it can be changed into a prime (18012721) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 772 + ... + 6051.

Almost surely, 2^18012720 is an apocalyptic number.

18012720 is a gapful number since it is divisible by the number (10) formed by its first and last digit.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 18012720, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (30462336).

18012720 is an abundant number, since it is smaller than the sum of its proper divisors (42911952).

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

18012720 is a wasteful number, since it uses less digits than its factorization.

18012720 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 6850 (or 6844 counting only the distinct ones).

The product of its (nonzero) digits is 224, while the sum is 21.

The square root of 18012720 is about 4244.1394887539. The cubic root of 18012720 is about 262.1358579045.

The spelling of 18012720 in words is "eighteen million, twelve thousand, seven hundred twenty".