1218723840 has 480 divisors, whose sum is σ = 4718448000. Its totient is φ = 297271296.

The previous prime is 1218723787. The next prime is 1218723841. The reversal of 1218723840 is 483278121.

It is a tau number, because it is divible by the number of its divisors (480).

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

It is a junction number, because it is equal to n+sod(n) for n = 1218723795 and 1218723804.

It is not an unprimeable number, because it can be changed into a prime (1218723841) by changing a digit.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 42024946 + ... + 42024974.

It is an arithmetic number, because the mean of its divisors is an integer number (9830100).

Almost surely, 2^1218723840 is an apocalyptic number.

1218723840 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 1218723840, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (2359224000).

1218723840 is an abundant number, since it is smaller than the sum of its proper divisors (3499724160).

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

1218723840 is an equidigital number, since it uses as much as digits as its factorization.

1218723840 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 90 (or 58 counting only the distinct ones).

The product of its (nonzero) digits is 21504, while the sum is 36.

The square root of 1218723840 is about 34910.2254361097. The cubic root of 1218723840 is about 1068.1570277885.

The spelling of 1218723840 in words is "one billion, two hundred eighteen million, seven hundred twenty-three thousand, eight hundred forty".