20288421 has 8 divisors (see below), whose sum is σ = 30056960. Its totient is φ = 13525596.

The previous prime is 20288419. The next prime is 20288441. The reversal of 20288421 is 12488202.

It is not a de Polignac number, because 20288421 - 2¹ = 20288419 is a prime.

It is a Harshad number since it is a multiple of its sum of digits (27), and also a Moran number because the ratio is a prime number: 751423 = 20288421 / (2 + 0 + 2 + 8 + 8 + 4 + 2 + 1).

It is a Duffinian number.

It is a Curzon number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (20288441) 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 7 ways as a sum of consecutive naturals, for example, 375685 + ... + 375738.

It is an arithmetic number, because the mean of its divisors is an integer number (3757120).

Almost surely, 2^20288421 is an apocalyptic number.

It is an amenable number.

20288421 is a deficient number, since it is larger than the sum of its proper divisors (9768539).

20288421 is an equidigital number, since it uses as much as digits as its factorization.

20288421 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 751432 (or 751426 counting only the distinct ones).

The product of its (nonzero) digits is 2048, while the sum is 27.

The square root of 20288421 is about 4504.2669769897. The cubic root of 20288421 is about 272.7403641898.

The spelling of 20288421 in words is "twenty million, two hundred eighty-eight thousand, four hundred twenty-one".