20661250 has 20 divisors (see below), whose sum is σ = 38729790. Its totient is φ = 8264000.

The previous prime is 20661241. The next prime is 20661257. The reversal of 20661250 is 5216602.

It can be written as a sum of positive squares in 5 ways, for example, as 2368521 + 18292729 = 1539^2 + 4277^2 .

It is not an unprimeable number, because it can be changed into a prime (20661257) by changing a digit.

It is a polite number, since it can be written in 9 ways as a sum of consecutive naturals, for example, 7015 + ... + 9514.

Almost surely, 2^20661250 is an apocalyptic number.

20661250 is a deficient number, since it is larger than the sum of its proper divisors (18068540).

20661250 is an equidigital number, since it uses as much as digits as its factorization.

20661250 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 16551 (or 16536 counting only the distinct ones).

The product of its (nonzero) digits is 720, while the sum is 22.

The square root of 20661250 is about 4545.4647727158. The cubic root of 20661250 is about 274.4008996364.

Adding to 20661250 its reverse (5216602), we get a palindrome (25877852).

The spelling of 20661250 in words is "twenty million, six hundred sixty-one thousand, two hundred fifty".