20620821 has 16 divisors (see below), whose sum is σ = 30019136. Its totient is φ = 12514176.

The previous prime is 20620807. The next prime is 20620823. The reversal of 20620821 is 12802602.

It is not a de Polignac number, because 20620821 - 2¹³ = 20612629 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 (20620823) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 775 + ... + 6468.

It is an arithmetic number, because the mean of its divisors is an integer number (1876196).

Almost surely, 2^20620821 is an apocalyptic number.

It is an amenable number.

20620821 is a deficient number, since it is larger than the sum of its proper divisors (9398315).

20620821 is a wasteful number, since it uses less digits than its factorization.

20620821 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 7332.

The product of its (nonzero) digits is 384, while the sum is 21.

The square root of 20620821 is about 4541.0154150806. The cubic root of 20620821 is about 274.2218043450.

The spelling of 20620821 in words is "twenty million, six hundred twenty thousand, eight hundred twenty-one".