2172420 has 84 divisors (see below), whose sum is σ = 6885900. Its totient is φ = 575424.

The previous prime is 2172397. The next prime is 2172427. The reversal of 2172420 is 242712.

It can be written as a sum of positive squares in 2 ways, for example, as 492804 + 1679616 = 702^2 + 1296^2 .

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 = 2172393 and 2172402.

It is not an unprimeable number, because it can be changed into a prime (2172427) by changing a digit.

It is a polite number, since it can be written in 27 ways as a sum of consecutive naturals, for example, 14506 + ... + 14654.

It is an arithmetic number, because the mean of its divisors is an integer number (81975).

2^2172420 is an apocalyptic number.

2172420 is a gapful number since it is divisible by the number (20) 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 2172420, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (3442950).

2172420 is an abundant number, since it is smaller than the sum of its proper divisors (4713480).

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

2172420 is a wasteful number, since it uses less digits than its factorization.

2172420 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 176 (or 159 counting only the distinct ones).

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

The square root of 2172420 is about 1473.9131589073. The cubic root of 2172420 is about 129.5133680291.

The spelling of 2172420 in words is "two million, one hundred seventy-two thousand, four hundred twenty".