1999440 has 60 divisors (see below), whose sum is σ = 6717204. Its totient is φ = 532992.

The previous prime is 1999423. The next prime is 1999441. The reversal of 1999440 is 449991.

It can be written as a sum of positive squares in 2 ways, for example, as 501264 + 1498176 = 708^2 + 1224^2 .

It is a tau number, because it is divible by the number of its divisors (60).

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

It is a junction number, because it is equal to n+sod(n) for n = 1999395 and 1999404.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1999441) by changing a digit.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 669 + ... + 2108.

2^1999440 is an apocalyptic number.

1999440 is a gapful number since it is divisible by the number (10) formed by its first and last digit.

It is an amenable number.

1999440 is an abundant number, since it is smaller than the sum of its proper divisors (4717764).

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

1999440 is a wasteful number, since it uses less digits than its factorization.

1999440 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2796 (or 2787 counting only the distinct ones).

The product of its (nonzero) digits is 11664, while the sum is 36.

The square root of 1999440 is about 1414.0155586131. The cubic root of 1999440 is about 125.9803446287.

The spelling of 1999440 in words is "one million, nine hundred ninety-nine thousand, four hundred forty".