1999011840 has 384 divisors, whose sum is σ = 7530757920. Its totient is φ = 451411968.

The previous prime is 1999011829. The next prime is 1999011841. The reversal of 1999011840 is 481109991.

It is a happy number.

It is a tau number, because it is divible by the number of its divisors (384).

It is a Harshad number since it is a multiple of its sum of digits (42).

It is a junction number, because it is equal to n+sod(n) for n = 1999011792 and 1999011801.

It is not an unprimeable number, because it can be changed into a prime (1999011841) by changing a digit.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 24084439 + ... + 24084521.

Almost surely, 2^1999011840 is an apocalyptic number.

1999011840 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 1999011840, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (3765378960).

1999011840 is an abundant number, since it is smaller than the sum of its proper divisors (5531746080).

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

1999011840 is an frugal number, since it uses more digits than its factorization.

1999011840 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 135 (or 100 counting only the distinct ones).

The product of its (nonzero) digits is 23328, while the sum is 42.

The square root of 1999011840 is about 44710.3102203507. The cubic root of 1999011840 is about 1259.7135151141.

The spelling of 1999011840 in words is "one billion, nine hundred ninety-nine million, eleven thousand, eight hundred forty".