1621625 has 8 divisors (see below), whose sum is σ = 2023944. Its totient is φ = 1297200.

The previous prime is 1621621. The next prime is 1621637. The reversal of 1621625 is 5261261.

It can be written as a sum of positive squares in 4 ways, for example, as 478864 + 1142761 = 692^2 + 1069^2 .

It is not a de Polignac number, because 1621625 - 2² = 1621621 is a prime.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 1621625.

It is not an unprimeable number, because it can be changed into a prime (1621621) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 6362 + ... + 6611.

It is an arithmetic number, because the mean of its divisors is an integer number (252993).

2^1621625 is an apocalyptic number.

It is an amenable number.

1621625 is a deficient number, since it is larger than the sum of its proper divisors (402319).

1621625 is an equidigital number, since it uses as much as digits as its factorization.

1621625 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 12988 (or 12978 counting only the distinct ones).

The product of its digits is 720, while the sum is 23.

The square root of 1621625 is about 1273.4304064220. The cubic root of 1621625 is about 117.4852856178.

Adding to 1621625 its reverse (5261261), we get a palindrome (6882886).

The spelling of 1621625 in words is "one million, six hundred twenty-one thousand, six hundred twenty-five".