20477021 has 4 divisors (see below), whose sum is σ = 21030492. Its totient is φ = 19923552.

The previous prime is 20476933. The next prime is 20477053. The reversal of 20477021 is 12077402.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 14784025 + 5692996 = 3845^2 + 2386^2 .

It is a cyclic number.

It is not a de Polignac number, because 20477021 - 2¹⁴ = 20460637 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (20471021) 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 3 ways as a sum of consecutive naturals, for example, 276680 + ... + 276753.

It is an arithmetic number, because the mean of its divisors is an integer number (5257623).

Almost surely, 2^20477021 is an apocalyptic number.

It is an amenable number.

20477021 is a deficient number, since it is larger than the sum of its proper divisors (553471).

20477021 is an equidigital number, since it uses as much as digits as its factorization.

20477021 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 553470.

The product of its (nonzero) digits is 784, while the sum is 23.

The square root of 20477021 is about 4525.1542515145. The cubic root of 20477021 is about 273.5828851522.

The spelling of 20477021 in words is "twenty million, four hundred seventy-seven thousand, twenty-one".