1722420 has 72 divisors (see below), whose sum is σ = 5975424. Its totient is φ = 393408.

The previous prime is 1722419. The next prime is 1722431. The reversal of 1722420 is 242271.

It is a Harshad number since it is a multiple of its sum of digits (18).

It is a junction number, because it is equal to n+sod(n) for n = 1722393 and 1722402.

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, 577 + ... + 1943.

It is an arithmetic number, because the mean of its divisors is an integer number (82992).

2^1722420 is an apocalyptic number.

1722420 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 1722420, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (2987712).

1722420 is an abundant number, since it is smaller than the sum of its proper divisors (4253004).

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

1722420 is a wasteful number, since it uses less digits than its factorization.

1722420 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1389 (or 1384 counting only the distinct ones).

The product of its (nonzero) digits is 224, while the sum is 18.

The square root of 1722420 is about 1312.4099969141. The cubic root of 1722420 is about 119.8706940498.

Adding to 1722420 its reverse (242271), we get a palindrome (1964691).

The spelling of 1722420 in words is "one million, seven hundred twenty-two thousand, four hundred twenty".