20420451 has 24 divisors (see below), whose sum is σ = 32149040.
Its totient is φ = 12807936.
The previous prime is 20420443. The next prime is 20420453. The reversal of 20420451 is 15402402.
It is not a de Polignac number, because 20420451 - 23 = 20420443 is a prime.
It is not an unprimeable number, because it can be changed into a prime (20420453) by changing a digit.
It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 6495 + ... + 9111.
Almost surely, 220420451 is an apocalyptic number.
20420451 is a deficient number, since it is larger than the sum of its proper divisors (11728589).
20420451 is a wasteful number, since it uses less digits than its factorization.
20420451 is an odious number, because the sum of its binary digits is odd.
The sum of its prime factors is 2660 (or 2637 counting only the distinct ones).
The product of its (nonzero) digits is 320, while the sum is 18.
The square root of 20420451 is about 4518.8993128858.
The cubic root of 20420451 is about 273.3307186279.
Adding to 20420451 its reverse (15402402), we get a palindrome (35822853).
The spelling of 20420451 in words is "twenty million, four hundred twenty thousand, four hundred fifty-one".