1999100 has 18 divisors (see below), whose sum is σ = 4338264. Its totient is φ = 799600.

The previous prime is 1999099. The next prime is 1999103. The reversal of 1999100 is 19991.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1999103) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 9896 + ... + 10095.

2^1999100 is an apocalyptic number.

1999100 is a gapful number since it is divisible by the number (10) formed by its first and last digit.

It is an amenable number.

1999100 is an abundant number, since it is smaller than the sum of its proper divisors (2339164).

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

1999100 is a wasteful number, since it uses less digits than its factorization.

1999100 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 20005 (or 19998 counting only the distinct ones).

The product of its (nonzero) digits is 729, while the sum is 29.

The square root of 1999100 is about 1413.8953285162. The cubic root of 1999100 is about 125.9732033382.

Multiplying 1999100 by its reverse (19991), we get a square (39964008100 = 199910²).

1999100 divided by its reverse (19991) gives a square (100 = 10²).

The spelling of 1999100 in words is "one million, nine hundred ninety-nine thousand, one hundred".