20850421 has 4 divisors (see below), whose sum is σ = 21035052. Its totient is φ = 20665792.

The previous prime is 20850409. The next prime is 20850437. The reversal of 20850421 is 12405802.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 12405802 = 2 ⋅6202901.

It can be written as a sum of positive squares in 2 ways, for example, as 4536900 + 16313521 = 2130^2 + 4039^2 .

It is a cyclic number.

It is not a de Polignac number, because 20850421 - 2⁷ = 20850293 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 20850392 and 20850401.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (20850461) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 92146 + ... + 92371.

It is an arithmetic number, because the mean of its divisors is an integer number (5258763).

Almost surely, 2^20850421 is an apocalyptic number.

It is an amenable number.

20850421 is a deficient number, since it is larger than the sum of its proper divisors (184631).

20850421 is a wasteful number, since it uses less digits than its factorization.

20850421 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 184630.

The product of its (nonzero) digits is 640, while the sum is 22.

The square root of 20850421 is about 4566.2261223027. The cubic root of 20850421 is about 275.2358131588.

The spelling of 20850421 in words is "twenty million, eight hundred fifty thousand, four hundred twenty-one".