1721400 has 96 divisors (see below), whose sum is σ = 5654400. Its totient is φ = 432000.

The previous prime is 1721383. The next prime is 1721407. The reversal of 1721400 is 41271.

It is a Harshad number since it is a multiple of its sum of digits (15).

It is a self number, because there is not a number n which added to its sum of digits gives 1721400.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1721407) 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, 11325 + ... + 11475.

It is an arithmetic number, because the mean of its divisors is an integer number (58900).

2^1721400 is an apocalyptic number.

1721400 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 1721400, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (2827200).

1721400 is an abundant number, since it is smaller than the sum of its proper divisors (3933000).

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

1721400 is a wasteful number, since it uses less digits than its factorization.

1721400 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 189 (or 180 counting only the distinct ones).

The product of its (nonzero) digits is 56, while the sum is 15.

The square root of 1721400 is about 1312.0213412898. The cubic root of 1721400 is about 119.8470272997.

Subtracting from 1721400 its product of nonzero digits (56), we obtain a square (1721344 = 1312²).

Adding to 1721400 its reverse (41271), we get a palindrome (1762671).

The spelling of 1721400 in words is "one million, seven hundred twenty-one thousand, four hundred".