1720620 has 108 divisors (see below), whose sum is σ = 5809440. Its totient is φ = 411840.

The previous prime is 1720619. The next prime is 1720633. The reversal of 1720620 is 260271.

1720620 = T₁₁₉ + T₁₂₀ + ... + T₂₂₈.

It is a happy number.

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 = 1720593 and 1720602.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 35 ways as a sum of consecutive naturals, for example, 21741 + ... + 21819.

2^1720620 is an apocalyptic number.

1720620 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 1720620, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (2904720).

1720620 is an abundant number, since it is smaller than the sum of its proper divisors (4088820).

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

1720620 is a wasteful number, since it uses less digits than its factorization.

1720620 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 116 (or 100 counting only the distinct ones).

The product of its (nonzero) digits is 168, while the sum is 18.

The square root of 1720620 is about 1311.7240563472. The cubic root of 1720620 is about 119.8289228877.

Adding to 1720620 its reverse (260271), we get a palindrome (1980891).

The spelling of 1720620 in words is "one million, seven hundred twenty thousand, six hundred twenty".