20025821 has 8 divisors (see below), whose sum is σ = 20277720. Its totient is φ = 19775808.

The previous prime is 20025787. The next prime is 20025823. The reversal of 20025821 is 12852002.

It can be written as a sum of positive squares in 4 ways, for example, as 1792921 + 18232900 = 1339^2 + 4270^2 .

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

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-20025821 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 20025793 and 20025802.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (20025823) 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, 35675 + ... + 36231.

It is an arithmetic number, because the mean of its divisors is an integer number (2534715).

Almost surely, 2^20025821 is an apocalyptic number.

It is an amenable number.

20025821 is a deficient number, since it is larger than the sum of its proper divisors (251899).

20025821 is a wasteful number, since it uses less digits than its factorization.

20025821 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 943.

The product of its (nonzero) digits is 320, while the sum is 20.

The square root of 20025821 is about 4475.0218993878. The cubic root of 20025821 is about 271.5585263863.

Adding to 20025821 its reverse (12852002), we get a palindrome (32877823).

The spelling of 20025821 in words is "twenty million, twenty-five thousand, eight hundred twenty-one".