18618721680 has 320 divisors, whose sum is σ = 66183264000. Its totient is φ = 4291854336.

The previous prime is 18618721619. The next prime is 18618721711. The reversal of 18618721680 is 8612781681.

It is a happy number.

It is a Harshad number since it is a multiple of its sum of digits (48).

It is an unprimeable number.

It is a polite number, since it can be written in 63 ways as a sum of consecutive naturals, for example, 5274156 + ... + 5277684.

It is an arithmetic number, because the mean of its divisors is an integer number (206822700).

Almost surely, 2^18618721680 is an apocalyptic number.

18618721680 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 18618721680, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (33091632000).

18618721680 is an abundant number, since it is smaller than the sum of its proper divisors (47564542320).

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

18618721680 is a wasteful number, since it uses less digits than its factorization.

18618721680 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 3666 (or 3660 counting only the distinct ones).

The product of its (nonzero) digits is 258048, while the sum is 48.

The spelling of 18618721680 in words is "eighteen billion, six hundred eighteen million, seven hundred twenty-one thousand, six hundred eighty".