1720400 has 120 divisors (see below), whose sum is σ = 4981824. Its totient is φ = 563200.

The previous prime is 1720399. The next prime is 1720421. The reversal of 1720400 is 40271.

It is a happy number.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 74789 + ... + 74811.

2^1720400 is an apocalyptic number.

1720400 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 1720400, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (2490912).

1720400 is an abundant number, since it is smaller than the sum of its proper divisors (3261424).

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

1720400 is a wasteful number, since it uses less digits than its factorization.

1720400 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 69 (or 58 counting only the distinct ones).

The product of its (nonzero) digits is 56, while the sum is 14.

The square root of 1720400 is about 1311.6401945656. The cubic root of 1720400 is about 119.8238155259.

Adding to 1720400 its reverse (40271), we get a palindrome (1760671).

The spelling of 1720400 in words is "one million, seven hundred twenty thousand, four hundred".