1918643680 has 24 divisors (see below), whose sum is σ = 4532796072. Its totient is φ = 767457408.

The previous prime is 1918643677. The next prime is 1918643689. The reversal of 1918643680 is 863468191.

It is a Smith number, since the sum of its digits (46) coincides with the sum of the digits of its prime factors.

It is a self number, because there is not a number n which added to its sum of digits gives 1918643680.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1918643689) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 5995602 + ... + 5995921.

It is an arithmetic number, because the mean of its divisors is an integer number (188866503).

Almost surely, 2^1918643680 is an apocalyptic number.

1918643680 is a gapful number since it is divisible by the number (10) formed by its first and last digit.

It is an amenable number.

1918643680 is an abundant number, since it is smaller than the sum of its proper divisors (2614152392).

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

1918643680 is a wasteful number, since it uses less digits than its factorization.

1918643680 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 11991538 (or 11991530 counting only the distinct ones).

The product of its (nonzero) digits is 248832, while the sum is 46.

The square root of 1918643680 is about 43802.3250524444. The cubic root of 1918643680 is about 1242.6002666623.

The spelling of 1918643680 in words is "one billion, nine hundred eighteen million, six hundred forty-three thousand, six hundred eighty".