1917788940 has 384 divisors, whose sum is σ = 6638284800. Its totient is φ = 457850880.

The previous prime is 1917788933. The next prime is 1917788993. The reversal of 1917788940 is 498877191.

It is a Harshad number since it is a multiple of its sum of digits (54).

It is an unprimeable number.

It is a polite number, since it can be written in 127 ways as a sum of consecutive naturals, for example, 19770972 + ... + 19771068.

It is an arithmetic number, because the mean of its divisors is an integer number (17287200).

Almost surely, 2^1917788940 is an apocalyptic number.

1917788940 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 1917788940, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (3319142400).

1917788940 is an abundant number, since it is smaller than the sum of its proper divisors (4720495860).

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

1917788940 is a wasteful number, since it uses less digits than its factorization.

1917788940 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 222 (or 214 counting only the distinct ones).

The product of its (nonzero) digits is 1016064, while the sum is 54.

The square root of 1917788940 is about 43792.5671775474. The cubic root of 1917788940 is about 1242.4157165170.

The spelling of 1917788940 in words is "one billion, nine hundred seventeen million, seven hundred eighty-eight thousand, nine hundred forty".