20810421 has 12 divisors (see below), whose sum is σ = 30569760. Its totient is φ = 13638120.

The previous prime is 20810407. The next prime is 20810443. The reversal of 20810421 is 12401802.

It is not a de Polignac number, because 20810421 - 2¹¹ = 20808373 is a prime.

It is a super-3 number, since 3×20810421³ (a number of 23 digits) contains 333 as substring.

It is a junction number, because it is equal to n+sod(n) for n = 20810394 and 20810403.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (20810221) by changing a digit.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 19065 + ... + 20126.

It is an arithmetic number, because the mean of its divisors is an integer number (2547480).

Almost surely, 2^20810421 is an apocalyptic number.

It is an amenable number.

20810421 is a deficient number, since it is larger than the sum of its proper divisors (9759339).

20810421 is a wasteful number, since it uses less digits than its factorization.

20810421 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 39256 (or 39253 counting only the distinct ones).

The product of its (nonzero) digits is 128, while the sum is 18.

The square root of 20810421 is about 4561.8440350367. The cubic root of 20810421 is about 275.0596939284.

The spelling of 20810421 in words is "twenty million, eight hundred ten thousand, four hundred twenty-one".