20464821 has 24 divisors (see below), whose sum is σ = 33710040. Its totient is φ = 11851776.

The previous prime is 20464817. The next prime is 20464823. The reversal of 20464821 is 12846402.

It can be written as a sum of positive squares in 4 ways, for example, as 5948721 + 14516100 = 2439^2 + 3810^2 .

It is not a de Polignac number, because 20464821 - 2² = 20464817 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (20464823) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 3156 + ... + 7133.

It is an arithmetic number, because the mean of its divisors is an integer number (1404585).

Almost surely, 2^20464821 is an apocalyptic number.

It is an amenable number.

20464821 is a deficient number, since it is larger than the sum of its proper divisors (13245219).

20464821 is a wasteful number, since it uses less digits than its factorization.

20464821 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 10325 (or 10322 counting only the distinct ones).

The product of its (nonzero) digits is 3072, while the sum is 27.

The square root of 20464821 is about 4523.8060303245. The cubic root of 20464821 is about 273.5285417287.

It can be divided in two parts, 204 and 64821, that added together give a square (65025 = 255²).

The spelling of 20464821 in words is "twenty million, four hundred sixty-four thousand, eight hundred twenty-one".