20661325 has 6 divisors (see below), whose sum is σ = 25620074. Its totient is φ = 16529040.

The previous prime is 20661323. The next prime is 20661367. The reversal of 20661325 is 52316602.

It can be written as a sum of positive squares in 3 ways, for example, as 249001 + 20412324 = 499^2 + 4518^2 .

It is not a de Polignac number, because 20661325 - 2¹ = 20661323 is a prime.

It is a Harshad number since it is a multiple of its sum of digits (25), and also a Moran number because the ratio is a prime number: 826453 = 20661325 / (2 + 0 + 6 + 6 + 1 + 3 + 2 + 5).

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 20661325.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (20661323) by changing a digit.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 413202 + ... + 413251.

Almost surely, 2^20661325 is an apocalyptic number.

20661325 is a gapful number since it is divisible by the number (25) formed by its first and last digit.

It is an amenable number.

20661325 is a deficient number, since it is larger than the sum of its proper divisors (4958749).

20661325 is an equidigital number, since it uses as much as digits as its factorization.

20661325 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 826463 (or 826458 counting only the distinct ones).

The product of its (nonzero) digits is 2160, while the sum is 25.

The square root of 20661325 is about 4545.4730226897. The cubic root of 20661325 is about 274.4012316596.

Adding to 20661325 its reverse (52316602), we get a palindrome (72977927).

The spelling of 20661325 in words is "twenty million, six hundred sixty-one thousand, three hundred twenty-five".