1918138320 has 400 divisors, whose sum is σ = 7778073600. Its totient is φ = 437923584.

The previous prime is 1918138307. The next prime is 1918138357. The reversal of 1918138320 is 238318191.

It is a super-2 number, since 2×1918138320² = 7358509229304844800, which contains 22 as substring.

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

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 79 ways as a sum of consecutive naturals, for example, 2222209 + ... + 2223071.

It is an arithmetic number, because the mean of its divisors is an integer number (19445184).

Almost surely, 2^1918138320 is an apocalyptic number.

1918138320 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 1918138320, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (3889036800).

1918138320 is an abundant number, since it is smaller than the sum of its proper divisors (5859935280).

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

1918138320 is an equidigital number, since it uses as much as digits as its factorization.

1918138320 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 909 (or 880 counting only the distinct ones).

The product of its (nonzero) digits is 10368, while the sum is 36.

The square root of 1918138320 is about 43796.5560289847. The cubic root of 1918138320 is about 1242.4911590986.

The spelling of 1918138320 in words is "one billion, nine hundred eighteen million, one hundred thirty-eight thousand, three hundred twenty".