1621825 has 12 divisors (see below), whose sum is σ = 2081340. Its totient is φ = 1252160.

The previous prime is 1621819. The next prime is 1621843. The reversal of 1621825 is 5281261.

It can be written as a sum of positive squares in 6 ways, for example, as 1296 + 1620529 = 36^2 + 1273^2 .

It is not a de Polignac number, because 1621825 - 2⁵ = 1621793 is a prime.

It is a Harshad number since it is a multiple of its sum of digits (25).

It is a self number, because there is not a number n which added to its sum of digits gives 1621825.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 394 + ... + 1843.

It is an arithmetic number, because the mean of its divisors is an integer number (173445).

2^1621825 is an apocalyptic number.

It is an amenable number.

1621825 is a deficient number, since it is larger than the sum of its proper divisors (459515).

1621825 is a wasteful number, since it uses less digits than its factorization.

1621825 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2276 (or 2271 counting only the distinct ones).

The product of its digits is 960, while the sum is 25.

The square root of 1621825 is about 1273.5089320456. The cubic root of 1621825 is about 117.4901153598.

It can be divided in two parts, 16218 and 25, that multiplied together give a triangular number (405450 = T₉₀₀).

The spelling of 1621825 in words is "one million, six hundred twenty-one thousand, eight hundred twenty-five".