20621305 has 8 divisors (see below), whose sum is σ = 24814152. Its totient is φ = 16451328.

The previous prime is 20621299. The next prime is 20621309. The reversal of 20621305 is 50312602.

It is a happy number.

It can be written as a sum of positive squares in 4 ways, for example, as 622521 + 19998784 = 789^2 + 4472^2 .

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 20621305 - 2⁵ = 20621273 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (20621309) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 3664 + ... + 7393.

It is an arithmetic number, because the mean of its divisors is an integer number (3101769).

Almost surely, 2^20621305 is an apocalyptic number.

It is an amenable number.

20621305 is a deficient number, since it is larger than the sum of its proper divisors (4192847).

20621305 is a wasteful number, since it uses less digits than its factorization.

20621305 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 11435.

The product of its (nonzero) digits is 360, while the sum is 19.

The square root of 20621305 is about 4541.0687068134. The cubic root of 20621305 is about 274.2239497868.

Adding to 20621305 its reverse (50312602), we get a palindrome (70933907).

The spelling of 20621305 in words is "twenty million, six hundred twenty-one thousand, three hundred five".